atan() Mathematics Function atan() Calculate inverse tangent #include <math.h> double atan(arg) double arg; atan calculates the inverse tangent of arg, which may be any real number. The result will be in the range [-P/2, P/2]. ***** Example ***** For an example of this function, see the entry for acos. ***** See Also ***** errno, mathematics library COHERENT Lexicon Page 1