I am familiar with the basics of atan2. The doubt I have in the computation of atan2 came across from an image processing sofware.
This is a portion of the code segment when x>y. x and y are absolute values.
const_1 = 57.2836266;
const_2 = -18.6674461;
const_3 = 8.91400051;
const_4 = -2.53972459;
c = sqrt(y/x);
c2 = c*c;
angleInTheta = (((const_4*c2 + const_3)*c2 + const_2)*c2 + const_1)*c;
What confuses me is the formula of angleInTheta. The results are perfectly correct when applied. I would like to know get a brief explanation of this formula.
Thanks,