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Jaewoo Song

### Categories

• Tech

Beam Search is a tree search algorithm based on “Best First Search” method used in various NLP tasks frequently.

As we can see from its name, Best First Search algorithm is a method that explores a graph by searching the most promising node based on certain rules, which is heuristic.

Likewise in Beam Search, we conduct decoding process searching through sequences while keeping the several best options.

This makes up for shortcomings of original decoding procedures in NLG tasks in seq2seq or transformer architectures.

The limitations of greedy decoding

The decoder in original seq2seq or transformer models makes the output sequence in greedy method.

In other words, we just select the most probable word at each time $t$, only considering previous tokens generated, not future candidates.

So we make the best decision in the current certain moment.

But this can lead to unwanted or defected outputs since the decoder does not find the most optimal result among all possible combinations.

This is a major problem not only in this case but also in usages of a greedy algorithm itself.

So we always need to verify that the greedy method we are using eventually gives us the optimal answer, but unfortunately the decoder in above models does not.

Let’s see an example.

Assume that we are going to make a sentence “I enjoy playing games with the video game console.”

As we can see, the decoder predicts exactly one word at a certain time $t$.

But we cannot assure that this “one word” is the best choice, which can be a unwanted token with slightly better probability than that of original desired one.

In above example, there is no problem that ‘the’ comes right after ‘playing’ since this does not destroy the overall structures or meanings of the sentence at this point.

So the model might choose ‘the’ instead of ‘games’.

After choosing it, we cannot undo the choice and this error is passed to next phases on and on.

Eventually, the whole sequence is defected only due to this first false choice.

Before going into the details of beam search, let’s check one simple naive solution.

How about checking all combinations of words to find an optimal result?

Needless to say, this is too time consuming since if we say that the total number of words is $V$ and the maximum length of sequences is $L$, then the time complexity becomes $O(V^L)$.

Obviously this takes too long so the beam search can be a reasonable option.

Application of the beam search

What we’re gonna do now is that keeping a few sequences with high probability to prevent one mistake from corrupting the entire output.

In other words, since we cannot check all combinations, a compromise can be searching the best result among selected several sequences.

Let’s say that the beam size is $k$, which is the number of branches we are going to keep.

The process of the beam search is as follows.

1. When decoding a token from previous completed sequence, take top $k$ words with higher probability.
2. Expanding all branches possible, choose top $k$ branches considering each total score.
3. Keep conducting the decoding steps with chosen $k$ branches.

For example, if we set $k=2$, then the whole procedure goes like below description.

The figure is quite clumsy, but I think this will help you to understand how the beam search works.

And many people might be curious about several things, so we will look into it from now on.

First, the beam search does not guarantee the optimal answer, as you can see.

It just expands the search space so that we don’t miss possible better sequences, but it does not make us consider all combinations.

But it is certainly more effective than exhaustive search and gives us a quite better result than original greedy method does.

Second, it is not certain to decide when to stop decoding in beam search.

In greedy search, we just have to stop once the end token comes out, but the beam search has many hypotheses that have different termination timings.

One way is to set desired sequence number $n$.

If we meet the end token in one branch, then we just keep this sequence and continue to explore another branches using beam search.

Once the number of kept results become $n$, then we stop decoding and choose the best sequence.

Another way is to set a hyperparameter $T$ which specifies the certain time step to stop.

So we just keep decoding until the step reaches $T$, then get decoded sequences.

But there is one problem.

Sequentially choosing one word can be considered as multiplying each conditional probability to total score. (Or adding each log value to total log probability.)

Since the probability is between $0$ and $1$, choosing more words makes the total score smaller.

In other words, the longer the sentence is, the more disadvantageous it is to be chosen, which is not fair.

So there is a way to normalize scores by the length as follows.

$\frac{1}{t}\sum^{t}_{1}logP(y_i \mid y_1, y_2, ... y_{i-1}, x)$

So this is about beam search so far.

It is common method to generate a better result in many NLG tasks, such as Neural Machine Translation, Dialogue system, Text summarization, etc.

Although it is a bit complicated to implement into codes, it is certainly worth knowing.

Lecture 8: Machine Translation, Sequence-to-sequence and Attention . (2020, Jan 30). http://web.stanford.edu/class/cs224n/slides/cs224n-2020-lecture08-nmt.pdf.
Lecture 15: Natural Language Generation . (2020, Feb 25). http://web.stanford.edu/class/cs224n/slides/cs224n-2020-lecture15-nlg.pdf.


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## Site Tag Cloud

Vanilla 1.1.10 is a product of Lussumo. More Information: Documentation, Community Support.

• I have started an entry canonical extension.

• I am fiddling with an entry table - models for (infinity,1)-operads meant to allow to see 10+ different model categories and their main Quillen equivalences at one glance.

I guess there are better ways to typeset this. (Volunteers please feel free to lend a hand!) But for the time being I’ll settle with what I have so far.

• Added a section arithmetic D-modules. This is the optimal theory for p-adic cohomology of varieties over finite fields, since it has the six operations. This section is complementary to rigid cohomology.

• In

http://ncatlab.org/nlab/show/Lie+2-algebra, at

“… the differential respects the brackets: for all $x \in g_0$ and $h \in g_1$ we have

$\delta [x,h]=[x,\delta h]$

…”

is wrong. The equation should be:

$\delta \alpha(x,h) = [x,\delta h]$

Since I don’t know if I have the right to change an nLab entry,I post this here as an suggestion.

• Created a new entry on "special $\Delta$-spaces". Does anyone know of a better name?

The entry is poorly edited since I'm not fluent with the iTex syntax.
• I made some much-needed corrections at simplicial complex, directed mostly at errors which had been introduced by yours truly. I also created quasi-topological space (the notion due to Spanier).

I haven’t thought this through, but regarding the process of turning a simplicial complex into a simplicial set, the usual sequence of words seems to involve putting a non-canonical ordering on the set of vertices and then getting ordered simplices from that. But is there anything “wrong” with taking the composite

$SimpComp \hookrightarrow Set^{Fin_{+}^{op}} \stackrel{Set^{i^{op}}}{\to} Set^{\Delta^{op}}$

where the inclusion is the realization of simplicial complexes as concrete presheaves on nonempty finite sets, and the second arrow is pulling back along the forgetful functor $i$ from nonempty totally ordered finite sets to nonempty finite sets? This looks much more canonical.

• I hope Urs doesn’t mind my inserting a not-too-serious but nevertheless amusing example at symplectomorphism.

• Someone set up lawvere theory, but did not add anything to it. They had previously done an edit to FinSet. The new page has a redirect from Lawvere+theory, so I don’t see what 88.104.160.245 is doing. Can someone check the edit at [[FinSet]. It looks as if the person knows some things and so has added a bit, but it is so long since I knew that stuff well so I cannot tell if it is a valid edit or not.

• I have created a stub on Volodin. I have been unable to find out more on him. Can anyone help?

• Started presentation of a category by generators and relations. This is probably an evil definition (there was an old discussion on this in the context of quotient category), and there is perhaps a more modern way to do this, so feel free to change the entry. I used “quotient category” as in CWM and mentioned that this is not the definition in the nLab.

• I have added some material into Vietoris complex relating to links with algebraic K-theory and some conjectures of Kapranov and Saito.

• The last two days Stephan Spahn was visiting me, and we chatted a lot about étaleness in cohesive ∞-toposes.

We found proofs that

• for every notion of infinitesimal cohesive neighbourhood

$i : \mathbf{H} \hookrightarrow \mathbf{H}_{th}$

the total space projections of locally constant $\infty$-stacks are formally étale;

• the formally étale morphisms with respect to any choice of infinitesimal cohesion satisfy all the axioms of axiomatic open maps (or rather their $\infty$-version, of course).

(These are to be written up. Requires plenty of 3d iterated $\infty$-pullback diagrams which are hard to typeset).

Recall – from synthetic differential infinity-groupoid – that for the infinitesimal cohesive neighbourhood

$i :$ Smooth∞Grpd $\hookrightarrow$ SynthDiff∞Grpd

the axiomatically formally étale morphisms between smooth manifolds are precisely the étale maps in the traditional sense.

Motivated by all this, I finally see, I think, what the correct definition of cohesive étale ∞-groupoid is:

simply: $X \in \mathbf{H}$ is an étale cohesive $\infty$-groupoid if it admits an atlas $X_0 \to X$ by a formally étale morphism in $\mathbf{H}$.

I have spelled out the proof now here that with this definition a Lie groupoid $\mathcal{G}$ is an étale groupoid in the traditional sense, precisely if it is cohesively étale when regarded as an object of the infinitesimal cohesive neighbourhood $Smooth \infty Grpd \hookrightarrow SynthDiff \infty Grpd$.

I hope to further expand on all this with Stephan. But I may be absorbed with other things. Next week I am in Goettingen, busy with a seminar on $L_\infty$-connections.

• I found in the disambiguation page basis an entry basis of a vector space missing, and so I created one. I have then cross-linked this with relevant existing entries, such as basis theorem. Also created a brief entry orthogonal basis in order to get rid of grayish links is some entries.

• In context of size issues on admissible structures (in the sense of DAG V) I wondered which closure properties (e.g. obviously its closed under pullbacks along relatively k-compact morphisms) the class of relatively k-compact (for a regular cardinal k) morphisms in a (∞,1)-category satisfies. Is there any reference concerning this?

• I needed an entry that lists references on twisted K-homology, so I created one. This made me notice that we currently lack an entry K-homology. I can try to create a stub for that a little later…

• the link to the picture in the entry Charles Wells is broken. Does anyone know how to fix it or have an alternative picture?

• Perhaps we need a page on Jean-Louis Koszul, and possibly an agreement on terminology / names for entries. Ben has created a page called Koszul, but usually single names like that would be used for the ’person’ page of that mathematician, so … The term in in any case (as adjective) is also used in various other contexts e.g. for operads, so possibly there needs to be some rationalisation. My thought would be to combine a page on Koszul (and the Wikipedia (English) page on him is poor, and includes some very poor translation from the French ) with a certain amount of disambiguation, however I am not an expert on things ’Koszul’ and this may not be the most efficient way to go.

• I created orbifold groupoids with some classes of groupoids whose elements I like to think of as ‘‘orbifold groupoids‘‘. It would be nice to have a discussion of the interelation of these classes there, too.

• I was in the process of creating an entry for Cartesian fibration of dendroidal sets, when by accident I suddently discovered that the degree-1 case of this had been considered before, by Claudio Hermida. So now I have also created a brief entry

• I thought it would be useful to supplement the entry operad with entries symmetric operad and planar operad, that amplify a bit more on the specifics of these respective flavors of the general notion, and that will allow us in other entries to link specifically to one of the two notions, when the choice is to be made explicit.

So far I have written (only) an Idea-section at symmetric operad with some comments.

To be expanded.

• I have created a bunch of stub entries such as iterated loop space object with little non-redundant content for the moment. I am filling the k-monoidal table. Please bear with me for the time being, while I add stuff.

• have created an entry k-monoidal table to be used for inclusion into the entries that it organizes (see for instance at infinite loop space).

Will now create at least stubs for the missing links.

• I have created an entry on the Steinberg group $St(R)$ of a ring $R$. The entry includes the Whitehead lemma.

• I have half-heartedly started adding something to Kac-Moody algebra. Mostly refrences so far. But I don’t have the time right now to do any more.

• Is the notion of local Kan extension in weak or infinity n-categories well defined. I know there is the infinity,1-case done by Lurie, but it is not local. I would define a Kan extension as the datum of a 1-morphism filling the usual diagram, with a 2-morphism that induces an equivalence of (n-2)-categories of morphisms between morphisms. You may do the same in the infinity,n case, if needed.

Is there a better definition?

The point is to define limits in weak n-categories using this. It is not simpler to define limit than to define Kan extensions.

Are there finer notions of local extensions, that use more explicitely the higher category structure?
• I have started a stub on this. (Isn’t there a nice nPOV interpretation of this?)

• A new contribution
• There is a strange glitch on this page: the geometric realization of a cubical set (see geometric realizationealization) below) tends to have the wrong homotopy type:

That is what appears but is not a t all what the source looks like:

the geometric realization of a cubical set (see [geometric realization](#geometric realization) below) tends to have the wrong homotopy type:

What is going wrong and how can it be fixed?

Another point : does anyone know anything about symmetric cubical sets?

• I made some edits at classifying topos to correct what I thought were some inaccuracies. One is that simplicial sets classify interval objects, but offhand I didn’t see the exact notion of linear interval over at interval object that would make this a correct sentence. In any event, I went ahead and defined the notion of linear interval as a model of a specified geometric theory.

The other is for local rings. I think when algebraic geometers refer to a sheaf of local rings, they refer to a sheaf of rings over a (sober) space all of whose stalks are local. I wasn’t sure that description would be kosher for a general (Grothendieck) topos $E$ since there may not be any “stalks” (i.e., points $Set \to E$) to refer to. In any case, it seems to me safer to give the geometric theory directly.

• Matan Prezma kindly pointed out the he has an article with a correction to what used to be prop. 2 at model structure on cosimplicial simplicial sets. (One has to use restricted totalization instead of ordinary totalization.)

I have corrected this and added the reference.

I also added to the entry a remark that makes the relation to descent objects explicit. Right now this is remark 2.

• at subgroup I have collected a list of links to $n$Lab entries of the form “xyz subgroup”. If anyone knows of more such entries (or does a more thorough search), please consider adding them!

• How is Majid's bialgebra cohomology related to GS cohomology for bialgebras?

I saw the recent paper by Shoikhet where GS cohomology is k-monoidally understood.

Is there a similar understanding of Majid's cohomology?

format: plain


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Semi-groupes intégraux de SL(2,$${\mathbb{R}})$$. Application à la théorie du contrôle. (Integral semigroups on SL(2,$${\mathbb{R}})$$. Application to control theory).(French)Zbl 0602.93005

The subject of this work is the controllability problem for a family F of right invariant vector fields on the standard Lie group SL(2,$${\mathbb{R}})$$. In particular, it is proven that F is controllable if and only if one of the following two cases occurs:
1) the cones generated by F and -F coincide and $$Lie(F)=sl(2,{\mathbb{R}});$$
2) the cones generated by F and -F differ but the cone generated by F contains a compact element.
The main result is applied to the controllability problem on $$GL^+(2,{\mathbb{R}})$$, on $$S^ 1$$ and on $${\mathbb{R}}^ 2\setminus \{0\}$$.
Reviewer: A.Bacciotti

MSC:

 93B05 Controllability 93B03 Attainable sets, reachability 93C10 Nonlinear systems in control theory 22E99 Lie groups


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# Understanding RLWE

While you do not need to fully understand RLWE to use Concrete, it is useful to know they exist, as they will be used under the hood to perform bootstrapping (which we will learn about later).

RLWE stands for Ring Learning With Errors and refers to the extension of LWE over the ring of polynomials with coefficients in a modular integer ring. It is also a computational problem conjectured to be hard to solve. RLWE enable packing multiple ciphertexts into a single polynomial, enabling SIMD-like homomorphic operations.

Concrete implements RLWE and VectorRLWE structs, but without the ability to perform SIMD-like operations on them. This will be available in a future release.

# Extracting an RLWE coefficient as an LWE

Since RLWE is an extension of LWE, you can extract one of the RLWE ciphertext polynomial coefficient as an LWE ciphertext.

RLWE instances are 2-dimensional: they hold a vector of ciphertexts, in which each coefficient is itself a plaintext. Thus, when extracting an LWE, we need to both specify the coefficient we want as well as the ciphertext from which to extract that coefficient. This is done via the extract_1_lwe function:

// extracting the 3rd coefficient from the 1st ciphertext// ciphertexts and coefficients are zero-indexedlet lwe_ciphertext: VectorLWE = rlwe_ciphertext.extract_1_lwe(2, 0)?;

# Converting an RLWE secret key into an LWE secret key

Converting an RLWESecretKey instance into an LWESecretKey is done using to_lwe_secret_key function:

// convert the RLWE secret key into an LWE secret keylet lwe_sk = rlwe_sk.to_lwe_secret_key();

# Converting an LWE secret key into an RLWE secret key

Sometimes, you might need to do the opposite operation, and convert an LWE secret key into an RLWE secret key. This works almost the same, the only difference being that you have to specify the polynomial size when you use the to_rlwe_secret_key method: This assumes that the LWE dimension is a multiple of $N$ (i.e,, the degree of the polynomial).

// convert the LWE secret key into an RLWE secret keylet rlwe_sk = lwe_sk.to_rlwe_secret_key(512)?;


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# Questions Asked onOctober 15, 2012

1. ## algebra

Which set represents a Pythagorean triple? 27, 38, 42 33, 44, 55 35, 38, 42 68, 72, 81 Which number completes the Pythagorean triple: 12, 16, ____? 18 20 22 24 A base ball diamond is square. The distance from home plate to first base is 90 feet. In feet,

2. ## physics

The 20-g centrifuge at NASA's Ames Research Center in Mountain View, California, is a horizontal, cylindrical tube 58 ft long and is represented in the figure below. Assume an astronaut in training sits in a seat at one end, facing the axis of rotation

3. ## Chemistry

Balance the equation and write the reaction-quotient expression, Qc. U(s) + F2 (g) UF6 (g)

4. ## Chemistry

The complete combustion of 1.283g of cinnamaldeyde (C9H8O, one of the compounds in cinnamon) in a bomb calorimeter (Ccalorimeter=3.841 kJ/C) produced an increase in temperature of 130.32 C. Calculate the molar enthalpy of combustion of cinnamaldehydy

5. ## physics

How much heat is necessary to change 500g of ice at-10 celsius to water at 20 celsius?

6. ## chemistry

Given the balanced equation for the decomposition of INO, and the rate of disappearance of INO, write the expressions for the rates of appearance of I2 and NO 2INO(g) ---> I2(g) + 2NO(g) Reactant: Product(I2): Product(NO): -∆[INO]/2∆t = ??/?? = ??/??

7. ## Chemistry Lab

Hydrogen gas was collected over water in a eudiometer at 26 degrees celcius when the atmospheric pressure was 756 mm Hg. What was the pressure of the H2 gas?

8. ## Chemistry

Phthalates used as plasticizers in rubber and plastic products are believed to act as hormone mimics in human. The value of deltaHcombustion for dimethylphthalate (C10H10O4) is 4685 kJ/mol. Assume 1.035 g of dimethylphthalate is combusted in a calorimeter

9. ## chemistry

Nitric oxide (NO) can be removed from gas-fired power-plant emissions by reaction with methane as follows: CH4(g) + 4NO(g) --> 2N2(g) + CO2(g) + 2H2O(g) Complete the equation relating the rates for each of the following: a) the rate of appearance of N2 to

10. ## PreCalculus

A piano tuner strikes a tuning fork for note A above middle C and sets in motion vibrations that can be modeled by the equation y = 0.001 sin 880 Pi(T). Find the amplitude and period for the function.

11. ## chemistry

for depolarization of 1 mole of KMnO4, the moles of H2O2 required is_________

12. ## Physics

A tennis ball is dropped from 1.80 m above the ground. It rebounds to a height of 1.00 m (assume down to be negative). (a) With what velocity does it hit the ground? (b) With what velocity does it leave the ground? (c) If the tennis ball were in contact

13. ## Calculus

f(theta)= 4sec(theta)+ 2tan(theta), 0 less than theta less than 2pi. find all critical numbers

14. ## Chemistry

Given N2(g) + 3H2 = 2NH3(g), which scenario will allow you to eventually reach an equillibrium mixture involving these chemicals? A. Place only H2 into a sealed vessel. B.Place only NH3 into a sealed vessel. C.Place only N2 into a sealed vessel. D.All of

15. ## physics

3. A satellite of mass 500 kg orbits the Earth with a period of 6000 s. The Earth has a mass of 5.98 x 1024 kg. (a) Calculate the magnitude of the Earth's gravitational force on the satellite. (b) Determine the altitude of the satellite above the Earth's

16. ## Physics

A surfer is catching a wave. Suppose she starts at the top of the wave with a speed of 1.3 m/s and moves down the wave until her speed increases to 8.0 m/s. The drop in her vertical height is 2.8 m. If her mass is 59 kg, how much work is done by the

17. ## Physics

As a moon follows its orbit around a planet, the maximum gravitational force exerted on the moon by the planet exceeds the minimum gravitational force by 28.2 %. Find the ratio rmax/rmin, where rmax is the moon's maximum distance from the center of the

18. ## Physics

7. A stock person at the local grocery store has the job of 1) picking up boxes of tomatoes from the stockroom floor, 2) accelerating to a comfortable speed, 3) Carrying the boxes to the tomato display at constant speed, 4) decelerating to a stop, and 5)

19. ## Chemistry

why is it important to add 1M HCl dropwise to the crucible?

20. ## geometry

Yuki just bought a big screen TV set. The screen has a diagonal measure of 40 in. If the screen is 32 in. wide, how high is it?

21. ## PHYSICS

A skateboarder starts at point A in the figure(Figure 1) and rises to a height of 2.64 m above the top of the ramp at point B. What was the skateboarder's initial speed at point A?

22. ## trig

A plane is flying 12,000 feet horizontally from a tall, vertical cliff. The angle of elevation from the plane to the top of the cliff is 45degrees, while the angle of depression from the plane to a point on the cliff at elevation 8000 feet is 14degrees.

23. ## Math

The number N of bacteria in a refrigerated food is given by N(T) = 10T2 − 20T + 700, 1 ¡Ü T ¡Ü 20where T is the temperature of the food in degrees Celsius. When the food is removed from refrigeration, the temperature of the food is given by T(t) = 5t

24. ## chemistry

The reaction Cl(g)+ O3(g) --> ClO(g)+ O2(g) is the first-order in both reactants. Determine the pseudo-first-order and second-order rate constants for the reaction from the data in the table below if the initial ozone concentration was ..0000000000825 M or

25. ## College Algebra

The campus of a college has plans to construct a rectangular parking lot on land bordered on one side by a highway. There are 720 feet of fencing available to fence the other three sides. Let x represent the length of each of the two parallel sides of

26. ## physics

A cyclist is coasting at a steady speed of 17m/s but enters a muddy stretch where the effective coefficient of friction is 0.60. What will be the speed upon emerging?

27. ## college chemistry

Please be specific! Briefly explain whether each if the following procedural errors would result in a high, low, or an unchanged calculated mass of Ca2+ in the analyzed tablet. a)a student had difficulty decanting the supernatant solution from the test

28. ## chemistry

2C6H6(l) + 15O2(g) --> 12CO2(g)+ 6H2O(g) how to calculate the ratio?

29. ## Math

Show how to make one addend a ten. Complete the new addition sentence. 22+49= ? ---- + ---- =

30. ## chemistry

The reaction Cl(g)+ O3(g) --> ClO(g)+ O2(g) is the first-order in both reactants. Determine the pseudo-first-order and second-order rate constants for the reaction from the data in the table below if the initial ozone concentration was ..0000000000825 M or

31. ## Literature

2. In The Call of the Wild, the bond between Buck and Thornton is best explained by observing that A. dog and man were like mirror opposites. [B. dog and man were both in touch with their primordial nature.] C. Buck had helped Thornton pay off his debts.

32. ## university physics

Two forces act on a 4.00-kg object in a manner that the object has an acceleration 3.00 m/s2 in a direction 20.0° north of east. The first force is 15.00 N in a direction 10.0° west of north. What is the second force?

33. ## elementary

Draw an array. Then write a fact family to describe your array

34. ## Calculus

A pebble is dropped into a pond, causing ripples in the form of concentric circles. The radius r of the outer ripple is increasing at a constant rate of 2 feet per second. When the radius is 10 feet, at what rate is the total area A of the disturbed water

35. ## math

The scatter plot shows the study times and test scores for a number of students. How long did the person who scored 81 study? A. 50 minutes B. 81 minutes C. 16 minutes D. 100 minutes helppppppp!!!!!

36. ## chemistry

an ionic equation has 2H+(AQ)on the left side and H2(g) on the right. Are these species spectators? explain.

37. ## physics

the frequency of middle C on a piano is 261.6hz. What is the wavelength of sound as it travels @room air and in water?

38. ## graphs Math

how could I redraw the graph so that the change in customers between the two months does not seem so great? Do I start from zero? Intervals by 5? Any other advice before I start?

39. ## Algebra

he spreadsheet shows the length of 3 movies in each of 3 categories. Choose the formula that could be used in cell B2. A B C D E 1 Type of Movie Movie 1 (min. long) Movie 2 (min. long) Movie 3 (min. long) Mean Length 2 Animated 72 63 84 73 3 Drama 92 104

40. ## Physics

A pitcher throws a 0.140-kg baseball, and it approaches the bat at a speed of 50.0 m/s. The bat does Wnc = 65.0 J of work on the ball in hitting it. Ignoring air resistance, determine the speed of the ball after the ball leaves the bat and is 25.0 m above

41. ## Physics

A 1600-kg car experiences a combined force of air resistance and friction that has the same magnitude whether the car goes up or down a hill at 32 m/s. Going up a hill, the car's engine produces 54 hp more power to sustain the constant velocity than it

42. ## Math

Show his to make one addend a ten. Complete the new addition sentence. 15+37=? ---- + ---- =

43. ## TRIG.

From a point 50 feet in front of a church, the angles of elevation to the base of the steeple and the top of the steeple are 35° and 47° 20', respectively. Find the height of the steeple. I missed class this day and have no idea how to go about this

44. ## Physics

A skier is gliding along at 5.0{\rm m/s} on horizontal, frictionless snow. He suddenly starts down a 15{\rm ^{\circ}} incline. His speed at the bottom is 15{\rm m/s} .

45. ## chemistry

Please be specific! Briefly explain whether each if the following procedural errors would result in a high, low, or an unchanged calculated mass of Ca2+ in the analyzed tablet. a)a student had difficulty decanting the supernatant solution from the test

46. ## Physics

Florence who weighs 120lb stands on a bathroom scale in an elevator. What will she see the scale read when the elevator is accelerating upward at 4.0 m/s^2 a) 120lb b) 135lb 3) 105lb d) 90lb

47. ## Newton's law

7. A uniform flexible chain of length l, with weight per unit length lamba, passes over a small, frictionless, massless pulley. It is released from a rest position with a length of chain x hanging from one side and a length l-x from the other side. Find

48. ## Algebra

A school planned to buy x calculators for a total cost of Ksh 16200. The supplier agreed to offer a discount of Ksh 60 per calculator. The school was the able to get three extra calculators for the same amount of money. (a) Write an expression in terms of

49. ## physics

A man claims he can safely hold on to a 11.90 kg child in a head-on collision with a relative speed of 117. mi/h lasting for 0.140 s as long as he has his seat belt on. (a) Find the magnitude of the average force needed to hold onto the child.

50. ## chemistry

What is the bonding continuum?

51. ## Chemistry

I am having such a hard time approaching this problem. It would be great if you can help me. 1.0 mole of CH4 react with 1.0 mole of O2 in a sealed container. (a) When the reaction is complete, what is the container? (b) How many moles of water are

52. ## Math( < > )

Find clues to the mystery number , the number is less than 800 but greater than 780 , it has 8 more 10's than 1's _________.

53. ## physics

A skier slides down a slope to the left at a constant speed.

54. ## Physics

An elevator weighing 10 000N is supported by a steel cable. Determine the tension in the cable when the elevator is accelerated upward at 3.0 m/s2 A) 7.0kN B) 10.0 kN C)11.6 kN D) 13.1 KN E) 40.0 kN

55. ## Physics

A farmhand pushes a 23kg bale of hay 4.0m across the floor of a barn. If she exerts a horizontal force of 91N on the hay, how much work has she done?

56. ## science

i need an acrostic poem of the word eukaryotic

57. ## Chemistry

Using data from the following reactions and applying Hess's law, calculate the heat change for the slow reaction of zinc with water (answer must be in kJ/mol Zn): Zn(s) + 2 H2O(l) ----> Zn^2+(aq) + 2 OH-(aq) + H2(g) (ΔHrxn = ?) H+(aq) + OH-(aq) ---->

58. ## Chem II

A sample of gas at 38 degrees Celsius occupies a volume of 2.97 L and exerts a pressure of 3.14 atm. The gas is heated to 118 degrees Celsius and the volume decreased to 1.04 L. Determine the new pressure exerted by the gas.

A charge is to be placed at the empty corner to make the net force at corner A point along the vertical direction. What charge (magnitude and algebraic sign) must be placed at the empty corner if the three charges have the same charge of +7.63 μC?

60. ## Chemistry

I am having such a hard time approaching this problem. It would be great if you can help me. 1.0 mole of CH4 react with 1.0 mole of O2 in a sealed container. (a) When the reaction is complete, what is the container? (b) How many moles of water are

In a Broadway performance an 80.0 kg actor swings from a 2.05 m long cable that is horizontal when he starts. At the bottom of his arc he picks up his 47.0 kg costar in an inelastic collision. (a) What is the velocity of the swinging actor just before

62. ## Chemistry

write the conjugate acid of this base. PO4^3-

63. ## geometry

Each side of a equilateral triangle measures 12 cm. Find the height, h of the triangle.

64. ## Chemistry

The alcohol in gasohol burns according to the reaction C2H5OH(l) + 3O2(g) --> 2CO2(g) + 3H2O how many grams of water are produced when 3.0 moles of C2H5OH are burned in an excess of oxygen gas?

65. ## Physics

Consider two vectors F~ 1 with magnitude 44 N inclined at 163 ◦ and F~ 2 with magnitude 72 N inclined at 236 ◦ , measured from the positive x axis with counterclockwise positive. What is the magnitude of the resultant vector F~ 1 + F~ 2 ? Draw the

66. ## Math

A school planned to buy x calculators for a total cost of Ksh 16200. The supplier agreed to offer a discount of Ksh 60 per calculator. The school was the able to get three extra calculators for the same amount of money. (a) Write an expression in terms of

67. ## Literature

5. As we find with most songs, in poetry [A. there's no specific point of view.] B. each couplet must rhyme. C. sound and content have equal weight. D. meanings are hidden in imprecise words.

68. ## chem

The complete combustion of 1.283g of cinnamaldeyde (C9H8O, one of the compounds in cinnamon) in a bomb calorimeter (Ccalorimeter=3.841 kJ/C) produced an increase in temperature of 130.32 C. Calculate the molar enthalpy of combustion of cinnamaldehydy

69. ## U.S history

okay i want to check and see if my answers are corrects before i submit my stuff. can someone help ? i think i know the answers but the questions are: 1. The cotton gin changed agriculture in the South by (1 point) A. simplifying the planting process. B.

70. ## Physics

A 1800-kg car experiences a combined force of air resistance and friction that has the same magnitude whether the car goes up or down a hill at 28 m/s. Going up a hill, the car's engine produces 52 hp more power to sustain the constant velocity than it

71. ## Physics URGENT!!!

A 4.02 kg steel ball strikes a massive wall at 11.8 m/s at an angle of 60.0° with the plane of the wall. It bounces off the wall with the same speed and angle, as shown in the figure below. If the ball is in contact with the wall for 0.174 s, what is the

72. ## Physics URGENT!!!

Gayle runs at a speed of 9.00 m/s and dives on a sled, initially at rest on the top of a frictionless, snow-covered hill, that has a vertical drop of 20.0 m. After she has descended a vertical distance of 4.00 m, her brother, who is initially at rest, hops

73. ## Government

Write a 1,000-word report on two different ways that you, as a young citizen, can become active in politics that would help promote causes that you believe in. You may choose a specific organization that is politically active. In the report, tell the goals

74. ## Math

A telephone is anchored to the ground by a long cable called a guy wire, at a point 5 meters from the base of the pole, the wire makes an angle of 72.5 degrees with the horizontal. What is the length of the guy wire? HELP ASAP! I forgot how to compute for

75. ## Math

Trish says that if 5/7 of her pencils are yellow, then 2/7 are not yellow. Is she correct. Explain

76. ## PHYSICS

At an amusement park, a swimmer uses a water slide to enter the main pool. The swimmer slides without friction, and descends through a vertical height of 2.98m. Find the swimmer's speed at the bottom of the slide if she starts with an initial speed of

77. ## Physics HELP!!

A student presses a book between his hands, as the drawing indicates. The forces that he exerts on the front and back cover are perpendicular to the book and are horizontal. The book weighs 29.7kg. The coefficient of static friction between his hands and

78. ## Chemistry

Liquid sodium is being considered as an engine coolant. How many grams of liquid sodium (minimum) are needed to absorb 3.60 MJ of energy (in the form of heat) if the temperature of the sodium is not to increased by more than 10.0 °C? Use CP = 30.8

79. ## Physics

A 74.1 kg climber is using a rope to cross between two peaks of a mountain as shown in the figure below. He pauses to rest near the right peak. Assume that the right side rope and the left side rope make angles of 48.0° and 11.16° with respect to the

80. ## Math

A baseball diamond is a square with sides 22.4m. The pitchers mound is 16.8m from home plate on the line joining home plate and second base. How far is the pitchers mound from first base? Step by step please.

81. ## physics

Standing on a balcony, you throuw your keys to a friend on the ground below. 1.2 seconds after releasing the keys, they have an instantaneous velocity of 14.8 m/s directed 53 degrees below horizontal. What initial velocity did you give them?

82. ## math

A water trough is 4 m long and its cross-section is an isosceles trapezoid which is 210 cm wide at the bottom and 280 cm wide at the top, and the height is 70 cm. The trough is not full. Give an expression for V, the volume of water in the trough in cm^3,

83. ## Math

Show how to make one addend a ten. Complete the new addition sentence. 38 + 25=? ---- + ---- =

84. ## physics

a student stands on an elevator scale at rest on the 64th floor of a building. the scale reads 847 N. As the elevator moves up the scales increases to 923 N, then decreases back to 847 N. the acceleration of gravity is 9.8m/s^2. Answer in units of m/s^2

85. ## english

Roman was an orphan who had barely survived in a war camp.

86. ## s.s.

"unemployment leads to wastage of man power resource" justifythe statement with suitable examples.

87. ## Physics

A little red wagon with mass 7.0kg moves in a straight line on a frictionless horizontal surface. It has an initial speed of4.00 m/s and then is pushed 3.0m in the direction of the initial velocity by a force with a magnitude of 10.0 N a.) Use the

88. ## Chemistry

How many milliliters of 7.00M HCl solution are needed to obtain 0.200mol of HCl?

89. ## Chemistry

How many moles of KBr are present in 120mL of a 0.290M solution?

90. ## College Chemistry

We will calculate the amount of acid to use in each titration. Assume that you are using 0.0512 M NaOH(aq). A good volume of NaOH(aq) to use per titration is 15mL. From this molarity and volume, the moles of NaOH can be calculated. Since the unknown acid

91. ## Calculus

Find the dervatives: 1. f(x)=(3x+1)e^x^2 2. y = e^(sin x) ln(x) 3. f(x)=(x^(2)+x)^23 4. f(x)=sin(2x)/cosx 5. square root of x/(3x+1) 6. f(x)=sin^4(3x=1)-sin(3x+1) 7. x+y=cos(xy) The answers I got: 1. 6x^(2)e^(x^2)+2xe^(x^2)+3e^(x^2) 2. e^sinx/x +

92. ## Math

An 8 meters bamboo pole is leaning against a coconut tree. The foot of the pole is 3 meters from the base of the tree. What angle does the pole make with the tree if the pole reaches up to the top of the tree? HELP PLEASE!

93. ## Physics

A little red wagon with mass 7.0kg moves in a straight line on a frictionless horizontal surface. It has an initial speed of4.00 m/s and then is pushed 3.0m in the direction of the initial velocity by a force with a magnitude of 10.0 N a.) Use the

94. ## Chemistry

The complete combustion of 1.283g of cinnamaldeyde (C9H8O, one of the compounds in cinnamon) in a bomb calorimeter (Ccalorimeter=3.841 kJ/C) produced an increase in temperature of 130.32 C. Calculate the molar enthalpy of combustion of cinnamaldehydy

95. ## earth

The global-mean surface temperature of the earth is about 288 degrees Kelvin. Use the Stefan-Boltzman law to calculate the radiative flux corresponding to an object with this temperature. [hint: use σT4 with σ = 5.67x10-8 Wm-2K-4 ]

96. ## math

meredith picked 4 times as many green apples as red apples. if she picked a total of 20 apples how many green apples did she pick?

97. ## Math

Mr Collins bowling league has 48 members. If the league splits into teams of 12 members each,how many equally sized teams will there be

98. ## Grammar, punctuation

Social history revealed that he lives with his aunt and uncle does not smoke or chew tobacco and reported drinking to intoxication once a month. My answer is; Social history revealed that he lives with his aunt and uncle, does not smoke or chew tobacco and

99. ## Literature

13. Scan this line from Cowley's poem: "its hills bent low within my reach." How many feet does this line contain? A. 5 B. 7 C. 6 [D. 4]

100. ## Grammar, punctuation

She experienced fever anorexia weakness and right-sided chest pain. I say the correct punctuation for this sentece is; She experienced fever, anorexia, weakness and right-sided chest pain.

101. ## science

if an object covers a large enough area of the water's surface, it can float on the water because of the________of water particles

102. ## chemistry ........................chemistry

Sodium Na+ Intense yellow Barium Ba++ Green Calcium Ca++ Brick red Copper Cu+ or Cu++ Blue-green Strontium Sr++ ? Lithium Li+ ? Sodium and potassium mixture Na+&K :yellow light Observations using the cobalt glass filter Sodium & potassium mixture

103. ## physics

Your physical therapist throws a baseball to you at a certain speed and you catch it. To increase the difficulty, the therapist is going to throw you a medicine ball whose mass is ten times the mass of the baseball. You are given the following choices.

104. ## Can you help me make my thesis sound clear & good

In the short story, "how much land does a man need," the author Leo Tolstoy would describe that human worth based on shallow measurements such as wealth and possessions make true love and humanity impossible because of greediness, the devil filling our

105. ## algebra

2st squared -s squared. S=4 t=8

106. ## Chemistry

Zinc dissolves in acid according to the balanced reaction: Zn(s) + 2H^+(aq) -> Zn^2+(aq) + H2(g) A sample of zinc is placed in the ice calorimeter. If 0.0657g of zinc causes a decrease of 0.109mL in the ice/water volume of the calorimeter, what is the

107. ## Calculus

Find dy/dx using implicit differentiation of xy + sin^2y=10350. Is it -y/(x+2siny)

108. ## College algebra

What is the domain for X³+2X²-9X-18

109. ## PHYSICS

A 0.26kg- rock is thrown vertically upward from the top of a cliff that is 32m high. When it hits the ground at the base of the cliff, the rock has a speed of 29m/s. 1) Assuming that air resistance can be ignored, find the initial speed of the rock ? m/s

110. ## Physics

A golf ball of mass 30.0 grams is struck by a 4.00 kg golf club for a time of 3.00 ms. If the golf ball obtains a velocity of 25.0 m/s after being struck then with what force did the club strike the golf ball? a. 2.50 N b. 7.50 N c. 250 N d. 750 N e. 25.0

111. ## Physics

A 0.40kg block is held against a compressed spring of stiffness 68.2N/m and compression 0.64m parallel to a 24 degree incline that is 1.27m long. The coefficient of kinetic friction between the block and the incline is 0.34. The external force holding the

112. ## Physics

A skier is gliding along at 5.0{\rm m/s} on horizontal, frictionless snow. He suddenly starts down a 15{\rm ^{\circ}} incline. His speed at the bottom is 15{\rm m/s} . What is the length of the incline? How long does it take him to reach the bottom?

113. ## Math

Janet drove 304 Kilometers and the trip took 4hours. How fast was Janet traveling?

114. ## physics

A spy in a speed boat is being chased down a river by government oﬃcials in a faster craft. Just as the oﬃcials’ boat pulls up next to the spy’s boat, both boats reach the edge of a 5.1 m waterfall. The spy’s speed is 17 m/s and the oﬃcials’

115. ## Language Arts

He fell like a leaf tossed down the wind, down, down, with one cry that overtook Daedalus far away. When he returned, and sought high and low for the poor boy, he saw nothing but the bird-like feathers afloat on the water, and he knew that Icarus was

116. ## Early Child Care

the ability to put an object or group of objects in a logical series based on a property of those objects is: A) seriation B) phonemic awareness C) classification D) attribution

117. ## Trig

From an observation tower that overlooks a runway, the angles of depression of point A, on one side of the runway, and point B, on the oppisite side of the runway are 6 degrees and 13 degreess respectivel. The points and the tower are in the same vertical

118. ## math

Use properties of logarithms to expand each logarithmic expression as much as possible. Where possible evaluate logarithmic expsressions without using a calculator. logb x^7

119. ## Physics

if you were on a 22.7 degree slope and an avalanche started 425 m up the slope, how much time would you have to get out of the way, there is no friction.

120. ## Chem II

What mass of oxygen gas exerts a pressure of 475 mm Hg in a volume of 1.25 L at a temperature of -22 degrees Celsius.

121. ## computer science

Write an Assembly program to determine the price of a car rental. The car being rented costs $45 per day and frequent renters get a$15 discount on the total bill. Get as input, the number of days rented and whether the user is part of the frequent renter

122. ## chemistry

2) Toluene, C6H5CH3, is a liquid similar to benzene, C6H6. It is the starting material for other substances, including trinitrotoluene (TNT). Find the molality of toluene in a solution that contains 25.8 g of toluene and 135 g of benzene.

123. ## Algebra

Give the domain of (f - g)(x) and (g of f)(x) where f(x)=3 -x and g(x) - ã(x)

124. ## algebra 1

A passenger plane and a jet leave att the same time from the same airport,traveling in opposite directions. The jet travels at twice the speed of the passenger plane. they are 2400 mi apart in 4 hours. Find the speed of the passenger plane and jet.

125. ## college orgo

calculate how to make 10 mL of 15:85 ethyl acetate:hexane solution from 2 mL of 5:95 ethyl acetate:hexane, using pure hexane and pure ethyl acetate.

126. ## grammar

If it tells you more about a noun, it’s a/an ________. A) adjective B) adverb C) noun D) pronoun E) verb I answered d

127. ## English

Identify the world in bold type. Do you know someone who can fix a lamp? (A) demonstrative pronoun (B) indefinite pronoun (C) interogative pronoun (D) relative pronoun (E) not a pronoun

128. ## physics

what frequency of sound travels in air @20 degree C has a wavelength equal to 1.7m?

129. ## Biology

How does long term survival of a species depend on resources that may be limited from time to time?

130. ## physics

A box of books weighing 324 N is shoved across the floor by a force of 527 N exerted downward at an angle of 35 below the hori- zontal. The acceleration of gravity is 9.81 m/s2 . If μk between the box and the floor is 0.59, how long does it take to move

131. ## math

there are 28 students in a class 16 are girls what fraction are boys

178. ## Math

If I make a porch that is 60 feet in length, 50 feet wide and 4 inches deep, how do I calculate the area, perimeter, and surface area of the porch? Can I multiply feet and inches in the same equation?

179. ## Physics

wo very small spheres are initially neutral and separated by a distance of 2.73 m. Suppose that 2.60E+13 electrons are removed from one sphere and placed on the other. What is the magnitude of the electrostatic force that acts on each sphere?

180. ## math

I am thinking of a number. If I add 4 to it, square the result, divide that result by 20, and subtract 4, the infal result is 1. What is my number

181. ## Statistics

Over a period of about nine months, 1,353 women reported the timing of each of their menstrual cycles. For the first cycle reported by each woman, the mean cycle time was 28.86 days, and the standard deviation of the 1,353 times was 4.24 days. (a)

182. ## social study

explian any three factor which lead to the incident known as bloody sunday

183. ## s.s.

who was the leader of the jacobin club?state any four laws indroduced by him

184. ## algebra

Using the equation y=-2x-5 a. The slope of this line is b. The y intercept of this line is c. The x intercept of this line is

185. ## Science 8R - Homework Qs. Check

If an object has mass of 70.5g and a volume of 64 cm(3), what is its Density? Will it sink or float and why? Answer - The Density of this object is 4512g/cm(3). It will sink because the amount of grams is a lot. Is the answer correct and good???? I

186. ## calculus

Differentiate: f(x)=(secx)/[1+sec(x)]

187. ## math

Suppose a certain economy's consumption function is as follows, where C(x) and x are measured in billions of dollars. C(x) = 0.76x^1.1 + 18.19 Find the marginal propensity to consume (dC/dx) when x = 7. (Round your answer to three decimal places.)

188. ## Physics

In a Physics laboratory class, an object of mass 2.1 kg, attached by massless strings to two hanging masses, m1= 1.0 kg and m2= 4.0 kg, is free to slide on the surface of the table. the coefficient of kinetic friction between m2 and the table is 0.30.

297. ## math

Find the following landmarks for 12,16,23,15,16,19,18

298. ## dounoon

(1) A sample of gas has a volume of 0.5 meter at 27 0degree and 1.5x10 Pa. What volume will this gas occupy if the temperature is raised to 117 0degree and the pressure lowered to 0.5x10 Pa.

299. ## math

y=(w-5)270 for w

300. ## Calc

deriv. y=x(sinx)(cosx)

301. ## science

changing the mass or volume of an object changes its density and ?

302. ## math

Someone said when you put together any groups, you can multiply. Explain why that is not correct.

303. ## US History

How would the French and Indian War first unite the colonists and then lead them to resent the British?

304. ## social studies

Are all aztecs able to wear feather headdress or just royalty and rich people?

305. ## English

What is can find in the following sentence: You can find properties of science in a basic clock. A. Main verb B. Helping verb C. Both D. Neither I say it is C Both, is this right?

306. ## Math

Change 300 mm3(cubed) to cm3(cubed). I have no idea how to work this out. Any help you can give me would be greatly appreciated!! Thanks

307. ## MATH

WALTER HAS A CAR PAYMENT OF 417.HOW MUCH WILL HIS CAR PAYMENTS TOTAL IN ONE YEAR?

308. ## Math

if the interest rate on a home mortgage is 9%, then each month you pay 0.75% of the unpaid balance in interest. if the unpaid balance on one such loan is \$60,000 at the beginning of a month, how much interest must be paid that month?

309. ## ENH275

How does a story employ verisimilitude?

310. ## s.s.

who is pinochet

311. ## s.s.

state the three demands of lenin's april theses?

312. ## Science

If Sam weights 114kg on earth what is his mass on the moon

313. ## calculus

differentiate: g(t)=tˆ3cos(t)

314. ## College Algebra

A piling supporting a bridge sits so that 1/4 of the piling is in the sand, 150 feet is in the water, and 3/5 of the piling is in the air. What is the total height of the piling?

315. ## Math

1/2 of class takes Spanish and 1/4 takes Chinese. 1/3 as many take French as Spanish. 8 takes French. No students takes more than one Language. How many takes Spanish? How many students take Chinese and how many students are in the class? Is this correct?

316. ## Calculus 1

differentiate f(x)=(1+sinˆ2x)ˆ6

317. ## Calculus

Find an equation of the tangent line to the curve of f (x) = x^3 − 8, at the point where the curve crosses the x-axis.

318. ## Grammar

A/an ________ and a connector is the same thing. A) conjunction B) preposition I answere B

319. ## aed 204

sexual harassment among students

320. ## Evolutionary Bio

Is Amborella considered a magnoliid, monocot, or eudicot and why?

321. ## grammar

Cowardice die many times before their death but brave once

322. ## Grammar

A relative pronoun is a connector, and the most commonly used relative pronouns are “that,” “which,” “who,” “whom,” “whose,” “whoever,” and “whomever.” True or False I answerd True

323. ## Math Rational Functions

What is the domain and range of 2x^2-18/x^2+3x-10

324. ## AP Calculus

if i define the function f(x)= x^3-x^2-3x-1 and h(x) = f(x)/g(x), then evaluate the limit (3h(x)+f(x)-2g(x), assuming you know the following things about h(x): h is continuous everywhere except when x = -1 lim as x approaches infinity of h(x) = infinity

325. ## math

when enlargeing sn object, why does the area increase diffrently than the preminter?

326. ## Math

What is the cube root of 192x to the 7th power?

327. ## social studies

what will obama do for for jobs, education and gun control? i am writing an persuasave essay in 6th grade and i need a fact about what obama will do for jobs education and gun control please make sure the facts are correct and NOT made up!

328. ## math

5/6 of 3 find the product

329. ## maths

what is prime triplet?

330. ## maths

x3+6x2+18x+13=0

331. ## geometry

solve for x if angle 1 and angle 2 are supplementary: angle 1= 5x+6 angle 2= 3x

332. ## math

write 8,042,176 in words

333. ## Math

How many 2/3 are in 3/4?

334. ## Religion

I need help interpreting this question, In Isaiah 38 how did Hezekiah feel when he found out he was going to die, some typical or expected things? thanks


text:
Question

# Find the area of the part of the plane 5x + 3y + z = 15 that lies in the first octant.

Integrals
Find the area of the part of the plane $$5x + 3y + z = 15$$ that lies in the first octant.