# C# | Math.Sqrt() Method

Last Updated : 06 Sep, 2022

In C#, Math.Sqrt() is a Math class method which is used to calculate the square root of the specified number. Sqrt is a slower computation. It can be cached for a performance boost. Syntax:

`public static double Sqrt(double d)`

Parameter:

d: Number whose square root is to be calculated and type of this parameter is System.Double.

Return Type: This method returns the square root of d. If d is equal to NaN, NegativeInfinity, or PositiveInfinity, that value is returned. The return type of this method is System.Double. Examples:

```Input  : Math.Sqrt(81)
Output : 9

Input  : Math.Sqrt(-81)
Output : NaN

Input  : Math.Sqrt(0.09)
Output : 0.3

Input  : Math.Sqrt(0)
Output : 0

Input  : Math.Sqrt(-0)
Output : 0```

Below C# programs illustrate the working of Math.Sqrt():

• Program 1: When the argument is positive double value then this method returns the square root of a given value.

## csharp

 `// C# program to illustrate the` `// Math.Sqrt() method` `using` `System;`   `class` `GFG {`   `    ``// Main Method` `    ``public` `static` `void` `Main()` `    ``{` `        ``double` `x = 81;`   `        ``// Input positive value, Output square root of x` `        ``Console.Write(Math.Sqrt(x));` `    ``}` `}`

Output:

`9`
• Program 2: When the argument is Negative, this method will return NaN.

## csharp

 `// C# program to illustrate the Math.Sqrt() ` `// method when the argument is Negative` `using` `System;`   `class` `GFG {`   `    ``// Main method` `    ``public` `static` `void` `Main()` `    ``{` `        ``double` `x = -81;`   `        ``// Input Negative value, Output square root of x` `        ``Console.Write(Math.Sqrt(x));` `    ``}` `}`

Output:

`NaN`
• Program 3: When the argument is double value with decimal places, then this method will return the square root of a given value.

## csharp

 `// C# program to illustrate the Math.Sqrt() ` `// method when the argument is double value` `// with decimal places` `using` `System;`   `class` `GFG {`   `    ``// Main Method` `    ``public` `static` `void` `Main()` `    ``{` `        ``double` `x = 0.09;`   `        ``// Input value with decimal places, ` `        ``// Output square root of x` `        ``Console.Write(Math.Sqrt(x));` `    ``}` `}`

Output:

`0.3`
• Program 4: When the argument is positive or negative Zero, then it will return the result as Zero.

## csharp

 `// C# program to illustrate the Math.Sqrt() ` `// method when the argument is positive ` `// or negative Zero` `using` `System;`   `class` `GFG {`   `    ``// Main Method` `    ``public` `static` `void` `Main()` `    ``{` `        ``double` `x = 0;`   `        ``// Input value positive Zero, Output` `        ``// square root of x` `        ``Console.WriteLine(Math.Sqrt(x));` `        ``double` `y = -0;`   `        ``// Input value Negative Zero,` `        ``// Output square root of y` `        ``Console.Write(Math.Sqrt(y));` `    ``}` `}`

Output:

```0
0```

Note: If the value is too large then it gives the compile time error as error CS1021: Integral constant is too large. Reference: https://msdn.microsoft.com/en-us/library/system.math.sqrt

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