Arctan formula

[ohsnap1319]

Does anyone know how to code the arctan of a number in C++??

[Disch]

http://cplusplus.com/reference/clibrary/cmath/atan/
or
http://cplusplus.com/reference/clibrary/cmath/atan2/

part of <cmath>:
http://cplusplus.com/reference/clibrary/cmath/

[ohsnap1319]

thanks!