Math.Sqrt(Double) Math.Sqrt(Double) Math.Sqrt(Double) Math.Sqrt(Double) Method

定义

返回指定数字的平方根。Returns the square root of a specified number.

public:
 static double Sqrt(double d);
public static double Sqrt (double d);
static member Sqrt : double -> double
Public Shared Function Sqrt (d As Double) As Double

参数

d
Double Double Double Double

将查找其平方根的数字。The number whose square root is to be found.

返回

下表中的值之一。One of the values in the following table.

d 参数d parameter 返回值Return value
零或正数Zero or positive d 的正平方根。The positive square root of d.
负数Negative NaN
等于 NaNEquals NaNNaN
等于 PositiveInfinityEquals PositiveInfinityPositiveInfinity

示例

一个正方形区域的平方根表示的长度的平方的任意一侧。The square root of the area of a square represents the length of any side of the square. 下面的示例在美国显示某些城市的区域,并提供了展示了每个城市的大小,如果它已由一个正方形。The following example displays the area of some cities in the United States and gives an impression of each city's size if it were represented by a square.

using System;

public class Example
{
   public static void Main()
   {
      // Create an array containing the area of some squares.
      Tuple<string, double>[] areas = 
                     { Tuple.Create("Sitka, Alaska", 2870.3), 
                       Tuple.Create("New York City", 302.6), 
                       Tuple.Create("Los Angeles", 468.7), 
                       Tuple.Create("Detroit", 138.8), 
                       Tuple.Create("Chicago", 227.1), 
                       Tuple.Create("San Diego", 325.2) };

      Console.WriteLine("{0,-18} {1,14:N1} {2,30}\n", "City", "Area (mi.)", 
                        "Equivalent to a square with:");

      foreach (var area in areas)
        Console.WriteLine("{0,-18} {1,14:N1} {2,14:N2} miles per side", 
                          area.Item1, area.Item2, Math.Round(Math.Sqrt(area.Item2), 2));        
   }
}
// The example displays the following output:
//    City                   Area (mi.)   Equivalent to a square with:
//    
//    Sitka, Alaska             2,870.3          53.58 miles per side
//    New York City               302.6          17.40 miles per side
//    Los Angeles                 468.7          21.65 miles per side
//    Detroit                     138.8          11.78 miles per side
//    Chicago                     227.1          15.07 miles per side
//    San Diego                   325.2          18.03 miles per side
Module Example
   Public Sub Main()
      ' Create an array containing the area of some squares.
      Dim areas() As Tuple(Of String, Double) = 
                     { Tuple.Create("Sitka, Alaska", 2870.3), 
                       Tuple.Create("New York City", 302.6), 
                       Tuple.Create("Los Angeles", 468.7), 
                       Tuple.Create("Detroit", 138.8), 
                       Tuple.Create("Chicago", 227.1), 
                       Tuple.Create("San Diego", 325.2) }

      Console.WriteLine("{0,-18} {1,14:N1} {2,30}", "City", "Area (mi.)", 
                        "Equivalent to a square with:")
      Console.WriteLine()
      For Each area In areas
        Console.WriteLine("{0,-18} {1,14:N1} {2,14:N2} miles per side", 
                          area.Item1, area.Item2, Math.Round(Math.Sqrt(area.Item2), 2))        
      Next
   End Sub
End Module
' The example displays the following output:
'    City                   Area (mi.)   Equivalent to a square with:
'    
'    Sitka, Alaska             2,870.3          53.58 miles per side
'    New York City               302.6          17.40 miles per side
'    Los Angeles                 468.7          21.65 miles per side
'    Detroit                     138.8          11.78 miles per side
'    Chicago                     227.1          15.07 miles per side
'    San Diego                   325.2          18.03 miles per side

适用于

另请参阅