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atan, atanf, atanl - arc tangent function
#include <math.h>
double atan(double x);
float atanf(float x);
long double atanl( long double x);
The atan() function calculates the arc tangent of x; that is
the value whose tangent is x.
The atan() function returns the
arc tangent in radians and the value is mathematically defined to be between
-PI/2 and PI/2 (inclusive).
SVID 3, POSIX, BSD 4.3, ISO 9899.
The float and long double variants are C99 requirements.
acos(3)
,
asin(3)
, atan2(3)
, cos(3)
, sin(3)
, tan(3)
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