acosh(), acoshf(), acoshl() — Calculate hyperbolic arccosine

Standards

Standards / Extensions C or C++ Dependencies

XPG4.2
C99
Single UNIX Specification, Version 3
C++ TR1 C99

 both  

Format

#define _XOPEN_SOURCE_EXTENDED 1
#include <math.h>

double acosh(double x);
C99: 
#define _ISOC99_SOURCE
#include <math.h>

float acoshf(float x);
long double acoshl(long double x);
C++ TR1 C99: 
#define _TR1_C99
#include <math.h>
float acosh(float x);  
long double acosh(long double x);

General description

The acosh functions compute the (nonnegative) arc hyperbolic cosine of x. A domain error occurs for arguments less than 1.
Note: The following table shows the viable formats for these functions. See IEEE binary floating-point for more information about IEEE Binary Floating-Point.
Function Hex IEEE
acosh X X
acoshf X X
acoshl X X

Returned value

If successful, acosh() returns the hyperbolic arccosine of its argument x.

If the value of x is less than 1.0, then the function returns 0.0 and sets errno to EDOM.

Special behavior for IEEE: If successful, the function returns the hyperbolic arccosine of its argument x.

If x is less than 1.0, the function sets errno to EDOM and returns NaNQ.

Related information

Parent topic: Library functions