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manpages-dev_3.35-0.1ubuntu1_all **NAME**

casinh, casinhf, casinhl - complex arc sine hyperbolic

**SYNOPSIS**

**#include** **<complex.h>**
**double** **complex** **casinh(double** **complex** __z__**);**
**float** **complex** **casinhf(float** **complex** __z__**);**
**long** **double** **complex** **casinhl(long** **double** **complex** __z__**);**
Link with __-lm__.

**DESCRIPTION**

The **casinh**() function calculates the complex arc hyperbolic sine of __z__.
If __y__ __=__ __casinh(z)__, then __z__ __=__ __csinh(y)__. The imaginary part of __y__ is chosen
in the interval [-pi/2,pi/2].
One has:
casinh(z) = clog(z + csqrt(z * z + 1))

**VERSIONS**

These functions first appeared in glibc in version 2.1.

**CONFORMING** **TO**

C99.

**SEE** **ALSO**

**asinh**(3), **cabs**(3), **cimag**(3), **csinh**(3), **complex**(7)

**COLOPHON**

This page is part of release 3.35 of the Linux __man-pages__ project. A
description of the project, and information about reporting bugs, can
be found at http://man7.org/linux/man-pages/.
2008-08-11 CASINH(3)