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);

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))

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