ATAN(3) BSD Library Functions Manual ATAN(3)NAMEatan — 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 [-π/2, +π/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 ALSOacos(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