# C# | Math.Sqrt() Method

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.

 `// 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.

 `// 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.

 `// 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.

 `// 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 its gives the compile time error as error CS1021: Integral constant is too large.

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