CASIN(3) Linux Programmer's Manual CASIN(3)

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.

These functions calculate the complex arc sine of z. 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))

These functions first appeared in glibc in version 2.1.

For an explanation of the terms used in this section, see attributes(7).
Interface Attribute Value
casin (), casinf (), casinl () Thread safety MT-Safe

C99, POSIX.1-2001, POSIX.1-2008.

clog(3), csin(3), complex(7)