tan [function]
tan( x )
returns the tangent of angle x in radians, as real
tan( 0 ); // real (0) tan( 1 ); // real (1.55741) tan( M_PI / 4 ); // real (1)
x in radians, as realtan( 0 ); // real (0) tan( 1 ); // real (1.55741) tan( M_PI / 4 ); // real (1)