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man:catanhf

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

NAME

`     catanh, catanhf, catanhl - complex arc tangents hyperbolic`

SYNOPSIS

`     #include <complex.h>`
```     double complex catanh(double complex z);
float complex catanhf(float complex z);
long double complex catanhl(long double complex z);```
`     Link with -lm.`

DESCRIPTION

```     These  functions calculate the complex arc hyperbolic tangent of z.  If
y = catanh(z), then z = ctanh(y).  The imaginary part of y is chosen in
the interval [-pi/2,pi/2].```
`     One has:`
`         catanh(z) = 0.5 * (clog(1 + z) - clog(1 - z))`

VERSIONS

`     These functions first appeared in glibc in version 2.1.`

ATTRIBUTES

```     For   an   explanation   of   the  terms  used  in  this  section,  see
attributes(7).```
```     allbox; lbw30 lb lb l  l  l.   Interface Attribute Value  T{  catanh(),
catanhf(), catanhl() T}   Thread safety  MT-Safe```

CONFORMING TO

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

EXAMPLE

`     /* Link with "-lm" */`
```     #include  <complex.h>  #include <stdlib.h> #include <unistd.h> #include
<stdio.h>```
```     int main(int argc, char *argv[]) {
double complex z, c, f;```
```         if (argc != 3) {
fprintf(stderr, "Usage: %s <real> <imag>\n", argv[0]);
exit(EXIT_FAILURE);
}```
`         z = atof(argv[1]) + atof(argv[2]) * I;`
```         c = catanh(z);
printf("catanh() = %6.3f %6.3f*i\n", creal(c), cimag(c));```
```         f = 0.5 * (clog(1 + z) - clog(1 - z));
printf("formula  = %6.3f %6.3f*i\n", creal(f2), cimag(f2));```
`         exit(EXIT_SUCCESS); }`

`     atanh(3), cabs(3), cimag(3), ctanh(3), complex(7)`
```     This page is part of release 4.16 of the Linux  man-pages  project.   A
`                                2015-04-19                         CATANH(3)`