# C++ Math tan() Function

In this post today I am going to explain the C++ Math tan() Function.

The tangent of an angle provided in radians is found using this function.

## Syntax of tan() function:

Consider a radian ‘x’. The syntax would be:

``````float tan(float x);
double tan(double x);
long double tan(long double x);
double tan(integral x);  ``````

Note that if the value is an integral type, it will be converted to double.

### Parameter:

x: The value given in radian.

### Return Value:

It returns the tangent of an angle given in radian.

#### Example-1:

Let’s have a look at a basic case where x is positive.

```#include <iostream>
#include<math.h>
using namespace std;
int main()
{
float degree=10;
cout<<"Tangent of an angle is : "<<tan(radian);
return 0;
}  ```

Output:

``````Tangent of an angle is : 0.176236
``````

When the value of a degree is equal to10, the tan() function calculates the tangent of an angle.

#### Example-2:

Let’s look at a basic case where the degree value is negative.

```#include <iostream>
#include<math.h>
using namespace std;
int main()
{
float degree= -60;
cout<<"Tangent of an angle is :"<<tan(radian);
return 0;
}  ```

output:

``````Tangent of an angle is :-1.72993
``````

When the value of the degree is negative, such as-60, the tan() function calculates the tangent of an angle. 