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## C++ acosh()

Last Updated on Wednesday 5th Oct 2022

## arcosh

The C++ `acosh()` function returns the arc hyperbolic cosine of a number in radians and it takes a single argument.

### Syntax

```			```
acosh(x)

```

```

### Parameters

The `acosh()` function takes a one argument which is greater or equal to 1.

If the argument is less than 1, a domain error occurs.

### Return value

Returns a value in the range `[0, ∞]`.If the argument is less than 1, it returns `NaN` (not a number).

### acosh() prototype [As of C++ 11 standard]

```			```
double acosh(double x);
float acosh(float x);
long double acosh(long double x);
double acosh(T x); // For integral type

```

```

### Example 1: C++ acosh()

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

int main () {
double param, result;
param = 12.1212;
result = acosh(param);
printf ("The area hyperbolic cosine of %f is %f radians.\n", param, result);
return 0;
}

```

```

Output

```			```
The area hyperbolic cosine of 12.121200 is 3.186397 radians.

```

```

### Example 2 : C++ acosh() ( With Negative Value )

As i said, If the argument is less than 1 , then `acosh()` returns NaN i.e. not a number.

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

int main () {
double param, result;
param = -11.1;
result = acosh(param);
printf ("%f", result);
return 0;
}

```

```

Output

```			```
-nan

```

```