## C# Math.Atan() – Examples

In this tutorial, we will learn about the C# Math.Atan() method, and learn how to use this method to find the arc tangent of given double value, with the help of examples.

## Atan(Double)

Math.Atan(d) returns the angle whose tangent is the specified number `d`. The angle returned shall be in radians.

### Syntax

The syntax of Atan(d) method is

`Math.Atan(Double d)`

where

Return Value

The method returns value of type double.

### Example 1 – Math.Atan(1.0)

In this example, we will find the angle for which tangent value is 1.0. We shall print the result both in radians and in degrees.

We know that tan(45 degrees) = 1.0. So, we should get the PI/4 radians as return value.

C# Program

```using System;

class Example {
static void Main(string[] args) {
Double d = 1.0;

Double angle = Math.Atan(d);
Console.WriteLine(\$"Angle in degrees : {(180 / Math.PI) * angle}");
}
}```

Output

```Angle in radians : 0.785398163397448
Angle in degrees : 45```

### Example 2 – Math.Atan(0)

In this example, we will find the angle for which tangent value is 0.0. We know that tan(0 degrees) = 0. So, we should get the zero radians as return value.

C# Program

```using System;

class Example {
static void Main(string[] args) {
Double d = 0;

Double angle = Math.Atan(d);
Console.WriteLine(\$"Angle in degrees : {(180 / Math.PI) * angle}");
}
}```

Output

```Angle in radians : 0
Angle in degrees : 0```

### Example 3 – Atan(Positive Infinity)

In this example, we will find the angle for which tangent value is Positive Infinity. We know that tan(90 degrees) = + Infinity. So, we should get the PI/2 radians as return value.

C# Program

```using System;

class Example {
static void Main(string[] args) {
Double d = Double.PositiveInfinity;

Double angle = Math.Atan(d);
```Angle in radians : 1.5707963267949