# C++ tanh()

The tanh() function in C++ returns the hyperbolic tangent of an angle given in radians.

The function is defined in <cmath> header file.

`[Mathematics] tanh x = tanh(x) [In C++ Programming]`

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

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

The tanh() function takes a single argument in radians and returns the hyperbolic tangent of that angle in type `double`, `float` or `long double` type.

The hyperbolic tangent of x is given by,

## tanh() Parameters

The tanh() function takes a single mandatory argument representing a hyperbolic angle in radian.

## tanh() Return value

The tanh() function returns the hyperbolic tangent of the argument.

## Example 1: How tanh() function works in C++?

``````#include <iostream>
#include <cmath>
using namespace std;
int main()
{
double x = 0.50, result;
result = tanh(x);
cout << "tanh(x) = " << result << endl;

// x in Degrees
double xDegrees = 90;
x = xDegrees * 3.14159/180;

result = tanh(x);
cout << "tanh(x) = " << result << endl;

return 0;
}```
```

When you run the program, the output will be:

```tanh(x) = 0.462117
tanh(x) = 0.917152
```

## Example 2: tanh() function with integral type

``````#include <iostream>
#include <cmath>
using namespace std;
int main()
{
int x = 5;
double result;

result = tanh(x);
cout << "tanh(x) = " << result << endl;

return 0;
}```
```

When you run the program, the output will be:

`tanh(x) = 0.999909`