Angle from 2D unit vector?

Question

Given unit vector 0.5, 0.5 how could I find the angle (its direction),

is it

cos(x) + sin(y)?

Answer 1

Given y and x, the angle with the x axis is given by:

atan2(y,x) 

With (0.5, 0.5) the angle is:

radians:

In [2]: math.atan2(0.5,0.5) Out[2]: 0.7853981633974483 

degrees:

In [3]: math.atan2(0.5, 0.5)*180/math.pi Out[3]: 45.0 

Answer 2

#include <cmath>  double x = 0.5; double y = 0.5; double angleInRadians = std::atan2(y, x); double angleInDegrees = (angleInRadians / M_PI) * 180.0;