# asinh, asinhf, asinhl

Calculates the inverse hyperbolic sine.

## Syntax

``````double asinh( double x );
float asinhf( float x );
long double asinhl( long double x );
``````
``````float asinh( float x );  // C++ only
long double asinh( long double x );  // C++ only
``````

### Parameters

x
Floating-point value.

## Return Value

The asinh functions return the inverse hyberbolic sine (arc hyperbolic sine) of x. This function is valid over the floating-point domain. If x is a quiet NaN, indefinite, or infinity, the same value is returned.

Input SEH Exception _matherr Exception
± QNAN, IND, INF none none

## Remarks

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

## Requirements

asinh, asinhf, asinhl <math.h> <cmath> or <math.h<

For additional compatibility information, see Compatibility.

## Example

``````// crt_asinh.c
// Compile by using: cl /W4 crt_asinh.c
// This program displays the hyperbolic sine of pi / 4
// and the arc hyperbolic sine of the result.

#include <math.h>
#include <stdio.h>

int main( void )
{
double pi = 3.1415926535;
double x, y;

x = sinh( pi / 4 );
y = asinh( x );
printf( "sinh( %f ) = %f\n", pi/4, x );
printf( "asinh( %f ) = %f\n", x, y );
}
``````
``````sinh( 0.785398 ) = 0.868671
asinh( 0.868671 ) = 0.785398
``````