ACOSH(3) NEWLIB ACOSH(3)NAME
1.4 `acosh', `acoshf'--inverse hyperbolic cosine
SYNOPSIS
#include <math.h>
double acosh(double X);
float acoshf(float X);
DESCRIPTION
`acosh' calculates the inverse hyperbolic cosine of X. `acosh' is
defined as
log(X + sqrt(X*X-1))
X must be a number greater than or equal to 1.
`acoshf' is identical, other than taking and returning floats.
RETURNS
`acosh' and `acoshf' return the calculated value. If X less than 1,
the return value is NaN and `errno' is set to `EDOM'.
You can change the error-handling behavior with the non-ANSI `math‐
err' function.
PORTABILITY
Neither `acosh' nor `acoshf' are ANSI C. They are not recommended for
portable programs.
SEE ALSOacosh is part of the library. The full documentation for is maintained
as a Texinfo manual. If info and are properly installed at your site,
the command
info
will give you access to the complete manual.
NEWLIB April 2010 ACOSH(3)
