# MathF.Cos() Method in C# with Examples

• Last Updated : 04 Apr, 2019

MathF.Cos(Single) is an inbuilt MathF class method which returns the cosine of a given float value argument(specified angle).

Syntax: public static float Cos (float x);
Here, x is the angle(measured in radian) whose cosine is to be returned and the type of this parameter is System.Single.

Return Value: This method will return the cosine of x of type System.Single. If x is equal to NegativeInfinity, PositiveInfinity, or NaN, then this method returns NaN.

Below are the programs to illustrate the use of the above-discussed method:

Example 1:

 `// C# program to illustrate the``// MathF.Cos(Single) Method``using` `System;`` ` `class` `GFG{`` ` `    ``// Main Method``    ``public` `static` `void` `Main(String[] args)``    ``{``        ``float` `a = 45f;`` ` `        ``// converting value to radians``        ``float` `b = (a * (MathF.PI)) / 180;`` ` `        ``// using method and displaying result``        ``Console.WriteLine(MathF.Cos(b));`` ` `        ``a = 54f;`` ` `        ``// converting value to radians``        ``b = (a * (MathF.PI)) / 180;`` ` `        ``// using method and displaying result``        ``Console.WriteLine(MathF.Cos(b));``        ``a = 70f;`` ` `        ``// converting value to radians``        ``b = (a * (MathF.PI)) / 180;`` ` `        ``// using method and displaying result``        ``Console.WriteLine(MathF.Cos(b));``    ``}``}`

Output:

```0.7071068
0.5877852
0.34202
```

Example 2: To show the working of MathF.Cos() method when the argument is NaN or Infinity.

 `// C# program to illustrate the``// MathF.Cos(Single) method ``using` `System;`` ` `class` `GFG {`` ` `    ``// Main Method``    ``public` `static` `void` `Main(String[] args)``    ``{`` ` `         ``// taking infinity values``        ``float` `positiveInfinity = ``float``.PositiveInfinity;``        ``float` `negativeInfinity = ``float``.NegativeInfinity;`` ` `        ``// taking NaN ``        ``float` `nan = ``float``.NaN;`` ` `        ``float` `result;`` ` `        ``// Here argument is negative infinity,``        ``// so the output will be NaN``        ``result = MathF.Cos(negativeInfinity);``        ``Console.WriteLine(result);`` ` `        ``// Here argument is positive infinity,``        ``// so the output will also be NaN``        ``result = MathF.Cos(positiveInfinity);``        ``Console.WriteLine(result);`` ` `        ``// Here argument is NaN, output will be NaN``        ``result = MathF.Cos(nan);``        ``Console.WriteLine(result);``    ``}``}`

Output:

```NaN
NaN
NaN
```

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