tan - tangent function
#include <math.h> double tan(double x);
The tan() function returns the tangent of x, where x is given in radians.
SVID 3, POSIX, BSD 4.3, ISO 9899
acos(3), asin(3), atan(3), atan2(3), cos(3), sin(3) 1993-06-08 TAN(3)