atan()

NAME

atan(), atanf() - arc tangent function of one variable

SYNOPSIS

#include <math.h>


double atan (double x)
float atanf (float x)

DESCRIPTION

The atan(3) and atanf(3) functions compute the principal value of the arc tangent of x.

The atanf(3) is nearly identical, except that it deals with float types rather than double.

RETURN VALUES

The atan(3) and atanf(3) functions return the arc tangent in the range [--.n/2, +-.n/2] radians. If x is 0, the functions return 0.

ERRORS

The atan(3) and atanf(3) functions can fail for the following reasons:

[EDOM]

The argument x is NaN.

[ERANGE]

The result underflows.

SEE ALSO

acos(3)

asin(3)

atan2(3)

cos(3)

cosh(3)

sin(3)

sinh(3)

tan(3)

tanh(3)