atan(3) BSD Library Functions Manual atan(3)
NAME
atan -- arc tangent function of one variable
SYNOPSIS
#include <math.h>
double
atan(double x);
long double
atanl(long double x);
float
atanf(float x);
DESCRIPTION
The atan() function computes the principal value of the arc tangent of x.
The result is in the range [-pi/2, +pi/2].
SPECIAL VALUES
atan(+-0) returns +-0.
atan(+-infinity) returns +-pi/2
VECTOR OPERATIONS
If you need to apply the atan() function to SIMD vectors or arrays, using
the following functions provided by the Accelerate.framework may give
significantly better performance:
#include <Accelerate/Accelerate.h>
vFloat vatanf(vFloat x);
void vvatanf(float *y, const float *x, const int *n);
void vvatan(double *y, const double *x, const int *n);
SEE ALSO
acos(3), asin(3), atan2(3), cos(3), cosh(3), sin(3), sinh(3), tan(3),
tanh(3), math(3) The atan() function conforms to ISO/IEC 9899:2011.
BSD December 11, 2006 BSD
Mac OS X 10.9.1 - Generated Mon Jan 6 19:04:56 CST 2014