Man Pages – Linux Manual Pages

carg, cargf, cargl – calculate the argument
USAGE
#include <complex.h>

double carg(double complex z);
float cargf(float complex z);
long double cargl(long double complex z);

Link with [...]

complex – basics of complex mathematics
USAGE
#include <complex.h>

DESCRIPTION
Complex numbers are numbers of the form z = a+b*i, where a and b are
real numbers and i = sqrt(-1), so that i*i = -1.
[...]

atan, atanf, atanl – arc tangent function
USAGE
#include <math.h>

double atan(double x);
float atanf(float x);
long double atanl( long double x);

Link with -lm.

DESCRIPTION
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