ATAN(3) BSD Library Functions Manual ATAN(3)NAMEatan — arc tangent function of one variable
SYNOPSIS
#include <math.h>
double
atan(double x);
DESCRIPTION
The atan() function computes the principal value of the arc tangent of x.
For a discussion of error due to roundoff, see math(3).
RETURN VALUES
The atan() function returns the arc tangent in the range [-π/2, +π/2]
radians.
SEE ALSOacos(3), asin(3), atan2(3), cos(3), cosh(3), sin(3), sinh(3), tan(3),
tanh(3), math(3),
STANDARDS
The atan() function conforms to ANSI X3.159-1989 (“ANSI C89”).
BSD June 4, 1993 BSD