HP 3000 Manuals

HP C/iX Library Reference Manual

atan 

Returns the arc tangent of the input value x.

Syntax 

     #include <math.h>
     double atan (double x);

Parameters 

x             A real number.

Return Values 

y             The arc tangent of x in the range of -pi/2 to pi/2.

Description 

The atan function returns the arc tangent of x, in the range -pi/2 to
pi/2.  No range or domain errors are possible.

See Also 

matherr(), ANSI C 4.5.2.3, POSIX.1 8.1

MPE/iX 5.0 Documentation