The Math.acos() function returns the arccosine (in radians) of a
number, that is ∀x∊[-1;1]
Math.acos(x) = arccos(x) = the unique y∊[0;π] such that cos(y)=x
The Math.acosh() function returns the hyperbolic arc-cosine of a
number, that is ∀x ≥ 1
Math.acosh(x) = arcosh(x) = the unique y ≥ 0 such that cosh(y) = x
The Math.asin() function returns the arcsine (in radians) of a
number, that is ∀x ∊ [-1;1]
Math.asin(x) = arcsin(x) = the unique y∊[-π2;π2] such that sin(y) = x
The Math.atan() function returns the arctangent (in radians) of a
number, that is Math.atan(x) = arctan(x) = the unique y ∊ [-π2;π2]such that
tan(y) = x
The Math.atanh() function returns the hyperbolic arctangent of a number,
that is ∀x ∊ (-1,1), Math.atanh(x) = arctanh(x) = the unique y such that
tanh(y) = x
The Math.cos() static function returns the cosine of the specified angle,
which must be specified in radians. This value is length(adjacent)/length(hypotenuse).
The Math.exp() function returns e^x, where x is the argument, and e is Euler’s number
(also known as Napier’s constant), the base of the natural logarithms.
The Math.random() function returns a floating-point, pseudo-random number
in the range 0–1 (inclusive of 0, but not 1) with approximately uniform distribution
over that range — which you can then scale to your desired range.
The implementation selects the initial seed to the random number generation algorithm;
it cannot be chosen or reset by the user.
The Math.tanh() function returns the hyperbolic tangent of a number, that is
tanh x = sinh x / cosh x = (e^x - e^-x)/(e^x + e^-x) = (e^2x - 1)/(e^2x + 1)