acosh, acoshf, acoshl


For the latest documentation on Visual Studio 2017 RC, see Visual Studio 2017 RC Documentation.

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