#include <math.h> double
atan (double x); float
atanf (float x);
DESCRIPTION
The
atan ();
and the
atanf ();
functions compute the principal value of the arc tangent of
Fa x .
For a discussion of error due to roundoff, see
math(3).
RETURN VALUES
The
atan ();
and the
atanf ();
function returns the arc tangent in the range
-words
Bq -/2 , +/2
radians.
