acosh()

compute the inverse hyperbolic cosine

Synopsis:

#include <math.h>
double acosh( double x );

Description:

The acosh() function computes the inverse hyperbolic cosine of x. A domain error occurs if the value of x is less than 1.0.

Returns:

the inverse hyperbolic cosine value.

When the argument is outside the permissible range, the matherr() function is called. Unless the default matherr() function is replaced, it will set the global variable errno to EDOM, and print a "DOMAIN error" diagnostic message using the stderr stream.

Examples:

#include <stdio.h>
#include <math.h>

void main()
  {
    printf( "%f\n", acosh( 1.5 ) );
  }

produces the output:

0.962424

Classification:

WATCOM

See also:

asinh(), atanh(), cosh(), errno, matherr()