complex sine function
Math library (libm, -lm)
These functions calculate the complex sine of z.
The complex sine function is defined as:
csin(z) = (exp(i * z) - exp(-i * z)) / (2 * i)
For an explanation of the terms used in this section, see attributes(7).
C11, POSIX.1-2008.
glibc 2.1. C99, POSIX.1-2001.