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; float radian=degree*3.14/180; 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; float radian=degree*3.14/180; 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.