# Math.Sqrt(Double) メソッド

## 定義

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

d
Double

#### 戻り値

Double

d パラメーター 戻り値
0 または正 d の正の平方根。
NaN
NaN と等しいNaN
PositiveInfinity と等しいPositiveInfinity

## 例

// Create an array containing the area of some squares.
Tuple<string, double>[] areas =
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("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