private static int sinh(LuaCallFrame callFrame, int nArguments) {
        BaseLib.luaAssert(nArguments >= 1, "Not enough arguments");
        double x = getDoubleArg(callFrame,1,names[SINH]);

        double exp_x = exp(x);
        double res = (exp_x - 1 / exp_x) * 0.5;

        callFrame.push(LuaState.toDouble(res));
        return 1;
    }
Rounds to keep <em>precision</em> decimals. Rounds towards even numbers.
@param x the number to round
@param precision the precision to round to. A precision of 3 will for instance round 1.65432 to 1.654
@return the rounded number
main/src/main/java/cgeo/geocaching/wherigo/kahlua/stdlib/MathLib.java