# C# Math - Atan() Method

The C# Atan() method returns arc tangent of a value. The return value will be in the range -𝜋/2 through 𝜋/2. In special cases it returns the following:

• If the argument is NaN, the method returns NaN.

Note: Atan() is the inverse of tan().

### Syntax

```public static double Atan(double arg);
```

### Parameters

 `arg` Specify the value.

### Return Value

Returns the arc tangent of the value.

### Example:

In the example below, Atan() method is used to find out the arc tangent of a given value.

```using System;

class MyProgram {
static void Main(string[] args) {
Console.WriteLine("Math.Atan(-2) = "
+ Math.Atan(-2));
Console.WriteLine("Math.Atan(-1) = "
+ Math.Atan(-1));
Console.WriteLine("Math.Atan(0) = "
+ Math.Atan(0));
Console.WriteLine("Math.Atan(1) = "
+ Math.Atan(1));
Console.WriteLine("Math.Atan(2) = "
+ Math.Atan(2));
Console.WriteLine("Math.Atan(Double.NaN) = "
+ Math.Atan(Double.NaN));
}
}
```

The output of the above code will be:

```Math.Atan(-2) = -1.10714871779409
Math.Atan(-1) = -0.785398163397448
Math.Atan(0) = 0
Math.Atan(1) = 0.785398163397448
Math.Atan(2) = 1.10714871779409
Math.Atan(Double.NaN) = NaN
```

❮ C# Math Methods

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