use Math::Trig;

$x = tan(0.9);
$y = acos(3.7);
$z = asin(2.4);

$halfpi = pi/2;

$rad = deg2rad(120);

Perl itself defines only three trigonometric functions: sin, cos, and atan2. The Math::Trig module overrides these with fancier versions and supplies all the rest of the trig functions, including tan, csc, cosec, sec, cot, cotan, asin, acos, atan, sinh, cosh, tanh, and many others. Additionally, the constant pi is defined, as are conversion functions like deg2rad and grad2rad. Support is provided for Cartesian, spherical, and cylindrical coordinates systems. This module makes implicit use of Math::Complex as needed (and vice versa) for computations requiring imaginary numbers.