CentOS 5.5

GNU/Linux	CentOS 5.5
	casinl(3)

CASIN

NAME

casin, casinf, casinl − complex arc sine

#include <complex.h>

double complex casin(double complex z);
float complex casinf(float complex z);
long double complex casinl(long double complex z);

Link with −lm.

The casin() function calculates the complex asin(). If y = casin(z), then z = csin(y). The real part of y is chosen in the interval [−pi/2,pi/2].

One has casin(z) = −i clog(iz+csqrt(1−z*z)).

C99