function
<cmath> <ctgmath>

# asinh

```     double asinh  (double x);
float asinhf (float x);
long double asinhl (long double x);
```
```     double asinh (double x);
float asinh (float x);
long double asinh (long double x);
Compute arc hyperbolic sine
Returns the arc hyperbolic sine of x, expressed in radians.

The arc hyperbolic sine is the inverse operation of the hyperbolic sine.

Header <tgmath.h> provides a type-generic macro version of this function.
Additional overloads are provided in this header (`<cmath>`) for the integral types: These overloads effectively cast x to a `double` before calculations (defined for T being any integral type).

This function is also overloaded in `<complex>` (see complex asinh).

### Parameters

x
Value whose arc hyperbolic sine is computed.

### Return Value

Arc hyperbolic sine of x, in radians.
One radian is equivalent to `180/PI` degrees.

### Example

 ``123456789101112`` ``````/* asinh example */ #include /* printf */ #include /* asinh, exp, cosh */ int main () { double param, result; param = exp(2) - cosh(2); result = asinh(param) ; printf ("The arc hyperbolic sine of %f is %f radians.\n", param, result); return 0; }``````

Output:
 ``` The arc hyperbolic sine of 3.626860 is 2.000000 radians. ```