# angle function in matlab formula

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Manu Chaudhary on 22 Sep 2022
Edited: James Tursa on 23 Sep 2022
Hi everyone,
I am trying to understand the functionality of angle function of matlab. I am trying to convert my matlab code(which we use for proof of concept) to C++ implementation.
input to angle function - 0.487936206701072 + 0.660466136142335i
output of angle function - 0.934517679414299
I know it must be tan-inverse(img/real) with some other constant.

Torsten on 22 Sep 2022
Edited: Torsten on 22 Sep 2022
It's all written in the MATLAB documentation of "angle":
Algorithms
angle takes a complex number z = x + iy and uses the atan2 function to compute the angle between the positive x-axis and a ray from the origin to the point (x,y) in the xy-plane.
Here is the "proof":
format long
z = 0.487936206701072 + 0.660466136142335*1i;
angle(z)
ans =
0.934517679414299
atan2(imag(z),real(z))
ans =
0.934517679414299
Manu Chaudhary on 23 Sep 2022
Yes, atan function works in c++ but not atan2.
Torsten on 23 Sep 2022