CATANH(3) | Library Functions Manual | CATANH(3)

# NAME

`catanh`, `catanhf`, `catanhl` — complex inverse hyperbolic tangent

# SYNOPSIS

Math Library (libm, -lm)
`#include <complex.h>`

double complex
`catanh`(double complex z);

float complex
`catanhf`(float complex z);

long double complex
`catanhl`(long double complex z);

# DESCRIPTION

The `catanh`(), `catanhf`() and `catanhl`() functions compute the complex inverse hyperbolic tangent of z.

For all complex floating-point numbers z,

    catanh(z) = -i catan(iz).

# RETURN VALUES

The `catanh`(), `catanhf`() and `catanhl`() functions return the complex inverse hyperbolic tangent of z with imaginary part in the interval [-Pi/2, Pi/2], and unbounded real part.

# SEE ALSO

cacosh(3), casinh(3)

# STANDARDS

The `catanh`(), `catanhf`() and `catanhl`() functions conform to ISO/IEC 9899:1999 (“ISO C99”).

June 7, 2025 | Debian