# tan() function with example in C++

C++ tan() function: Here, we are going to learn about the tan() function with example of cmath header in C++ programming language?
Submitted by IncludeHelp, on April 27, 2019

## C++ tan() function

tan() function is a library function of cmath header, it is used to find the tangent of the given number (angle), it accepts a number (x) and returns the tangent of angle x radians.

Syntax of tan() function:

```    tan(x);
```

Parameter(s): x – is the value of an angle in radians whose tangent to be calculated.

Return value: double – it returns double type value that is the tangent of given angle x radians.

Example:

```    Input:
float x = 2.45;

Function call:
tan(x);

Output:
-0.828017
```

### C++ code to demonstrate the example of tan() function

```// C++ code to demonstrate the example of
// tan() function

#include <iostream>
#include <cmath>
using namespace std;

// main() section
int main()
{
float x;

x = -10.23;
cout<<"tan("<<x<<"): "<<tan(x)<<endl;

x = 0;
cout<<"tan("<<x<<"): "<<tan(x)<<endl;

x = 2.45;
cout<<"tan("<<x<<"): "<<tan(x)<<endl;

return 0;
}
```

Output

```tan(-10.23): -1.04045
tan(0): 0
tan(2.45): -0.828017
```

Reference: C++ tan() function