The topic you requested is included in another documentation set. For convenience, it's displayed below. Choose Switch to see the topic in its original location.
We recommend using Visual Studio 2017

acosh, acoshf, acoshl


The new home for Visual Studio documentation is Visual Studio 2017 Documentation on

The latest version of this topic can be found at acosh, acoshf, acoshl.

Calculates the inverse hyperbolic cosine.

double acosh(  
   double x   
float acosh(  
   float x   
);  // C++ only  
long double acosh(  
   long double x  
);  // C++ only  
float acoshf(  
   float x   
long double acoshl(  
   long double x  


Floating-point value.

The acosh functions return the inverse hyberbolic cosine (arc hyperbolic cosine) of x. These functions are valid over the domain x ≥ 1. If x is less than 1, errno is set to EDOM and the result is a quiet NaN. If x is a quiet NaN, indefinite, or infinity, the same value is returned.

InputSEH Exception_matherr Exception
± QNAN, IND, INFnonenone
x < 1nonenone

When you use C++, you can call overloads of acosh that take and return float or long double values. In a C program, acosh always takes and returns double.

FunctionC headerC++ header
acosh, acoshf, acoshl<math.h><cmath>

For additional compatibility information, see Compatibility.

// crt_acosh.c  
// Compile by using: cl /W4 crt_acosh.c  
// This program displays the hyperbolic cosine of pi / 4  
// and the arc hyperbolic cosine of the result.  
#include <math.h>  
#include <stdio.h>  
int main( void )  
   double pi = 3.1415926535;  
   double x, y;  
   x = cosh( pi / 4 );  
   y = acosh( x );  
   printf( "cosh( %f ) = %f\n", pi/4, x );  
   printf( "acosh( %f ) = %f\n", x, y );  

cosh( 0.785398 ) = 1.324609  
acosh( 1.324609 ) = 0.785398  

Not applicable. To call the standard C function, use PInvoke. For more information, see Platform Invoke Examples.

Floating-Point Support
Long Double
cos, cosf, cosl, cosh, coshf, coshl
sin, sinf, sinl, sinh, sinhf, sinhl
asinh, asinhf, asinhl
tan, tanf, tanl, tanh, tanhf, tanhl
atanh, atanhf, atanhl