NAME
acosh —
inverse hyperbolic cosine
function
SYNOPSIS
#include
<math.h>
double
acosh(double
x);
long double
acoshl(long
double x);
float
acoshf(float
x);
DESCRIPTION
The
acosh()
function computes the principle value of the inverse hyperbolic cosine of
x. The result is in the range [0, +infinity].
SPECIAL VALUES
acosh(1) returns
+0.
acosh(x)
returns a NAN and raises the "invalid" floating-point exception
for x < 1.
acosh(+infinity)
returns +infinity.
VECTOR OPERATIONS
If you need to apply the acosh() function
to SIMD vectors or arrays, using the following functions provided by the
Accelerate.framework may give significantly better performance:
#include
<Accelerate/Accelerate.h>
vFloat
vacoshf(vFloat
x);
void
vvacoshf(float
*y, const float *x, const int
*n);
void
vvacosh(double
*y, const double *x, const int
*n);
SEE ALSO
STANDARDS
The acosh() function conforms to ISO/IEC
9899:2011.
HISTORY
The acosh() and
acoshf() function appeared in
4.3BSD.