Trigonometry

The trigonometrical functions are:

sin($f) sinh($f) asin($f) asinh($f)
cos($f) cosh($f) acos($f) acosh($f)
tan($f) tanh($f) atan($f) atan($f)
atan2($f1,$f2) returns the arc tangent of $f1/$f2.
hypot($f1,$f2) returns the length of the hypotenuse of a right-angle triangle with sides of length $f1 and $f2.
All angles are measured in radians. deg2rad($f) converts $f from degrees to radians. rad2deg($f) converts $f from radians to degrees. pi() returns an approximation of pi.