= private = protected
atan(p1)
Computes the arc tangent of x. Returns -PI/2..PI/2.
Domain: (-INFINITY, INFINITY)
Codomain: (-PI/2, PI/2)
Math.atan(0) #=> 0.0
static VALUE math_atan(VALUE obj, VALUE x) { Need_Float(x); return DBL2NUM(atan(RFLOAT_VALUE(x))); }