Math.Asin(Double) Method

Reference

Definition

Namespace:: System

Assembly:: System.Runtime.Extensions.dll

Assembly:: System.Runtime.dll

Assembly:: mscorlib.dll

Assembly:: netstandard.dll

Source:: Math.cs

Source:: Math.cs

Source:: Math.cs

Important

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Returns the angle whose sine is the specified number.

public:
 static double Asin(double d);

public static double Asin (double d);

static member Asin : double -> double

Public Shared Function Asin (d As Double) As Double

Parameters

d: Double

A number representing a sine, where d must be greater than or equal to -1, but less than or equal to 1.

Returns

Double

An angle, θ, measured in radians, such that -π/2 ≤ θ ≤ π/2.

-or-

NaN if d < -1 or d > 1 or d equals NaN.

Examples

The following example uses Asin to assist in the computation of the inner angles of a given trapezoid.

/// <summary>
/// The following class represents simple functionality of the trapezoid.
/// </summary>
using namespace System;

public ref class MathTrapezoidSample
{
private:
   double m_longBase;
   double m_shortBase;
   double m_leftLeg;
   double m_rightLeg;

public:
   MathTrapezoidSample( double longbase, double shortbase, double leftLeg, double rightLeg )
   {
      m_longBase = Math::Abs( longbase );
      m_shortBase = Math::Abs( shortbase );
      m_leftLeg = Math::Abs( leftLeg );
      m_rightLeg = Math::Abs( rightLeg );
   }


private:
   double GetRightSmallBase()
   {
      return (Math::Pow( m_rightLeg, 2.0 ) - Math::Pow( m_leftLeg, 2.0 ) + Math::Pow( m_longBase, 2.0 ) + Math::Pow( m_shortBase, 2.0 ) - 2 * m_shortBase * m_longBase) / (2 * (m_longBase - m_shortBase));
   }


public:
   double GetHeight()
   {
      double x = GetRightSmallBase();
      return Math::Sqrt( Math::Pow( m_rightLeg, 2.0 ) - Math::Pow( x, 2.0 ) );
   }

   double GetSquare()
   {
      return GetHeight() * m_longBase / 2.0;
   }

   double GetLeftBaseRadianAngle()
   {
      double sinX = GetHeight() / m_leftLeg;
      return Math::Round( Math::Asin( sinX ), 2 );
   }

   double GetRightBaseRadianAngle()
   {
      double x = GetRightSmallBase();
      double cosX = (Math::Pow( m_rightLeg, 2.0 ) + Math::Pow( x, 2.0 ) - Math::Pow( GetHeight(), 2.0 )) / (2 * x * m_rightLeg);
      return Math::Round( Math::Acos( cosX ), 2 );
   }

   double GetLeftBaseDegreeAngle()
   {
      double x = GetLeftBaseRadianAngle() * 180 / Math::PI;
      return Math::Round( x, 2 );
   }

   double GetRightBaseDegreeAngle()
   {
      double x = GetRightBaseRadianAngle() * 180 / Math::PI;
      return Math::Round( x, 2 );
   }

};

int main()
{
   MathTrapezoidSample^ trpz = gcnew MathTrapezoidSample( 20.0,10.0,8.0,6.0 );
   Console::WriteLine( "The trapezoid's bases are 20.0 and 10.0, the trapezoid's legs are 8.0 and 6.0" );
   double h = trpz->GetHeight();
   Console::WriteLine( "Trapezoid height is: {0}", h.ToString() );
   double dxR = trpz->GetLeftBaseRadianAngle();
   Console::WriteLine( "Trapezoid left base angle is: {0} Radians", dxR.ToString() );
   double dyR = trpz->GetRightBaseRadianAngle();
   Console::WriteLine( "Trapezoid right base angle is: {0} Radians", dyR.ToString() );
   double dxD = trpz->GetLeftBaseDegreeAngle();
   Console::WriteLine( "Trapezoid left base angle is: {0} Degrees", dxD.ToString() );
   double dyD = trpz->GetRightBaseDegreeAngle();
   Console::WriteLine( "Trapezoid left base angle is: {0} Degrees", dyD.ToString() );
}

/// <summary>
/// The following class represents simple functionality of the trapezoid.
/// </summary>
using System;

namespace MathClassCS
{
    class MathTrapezoidSample
    {
        private double m_longBase;
        private double m_shortBase;
        private double m_leftLeg;
        private double m_rightLeg;

        public MathTrapezoidSample(double longbase, double shortbase, double leftLeg, double rightLeg)
        {
            m_longBase = Math.Abs(longbase);
            m_shortBase = Math.Abs(shortbase);
            m_leftLeg = Math.Abs(leftLeg);
            m_rightLeg = Math.Abs(rightLeg);
        }

        private double GetRightSmallBase()
        {
            return (Math.Pow(m_rightLeg,2.0) - Math.Pow(m_leftLeg,2.0) + Math.Pow(m_longBase,2.0) + Math.Pow(m_shortBase,2.0) - 2* m_shortBase * m_longBase)/ (2*(m_longBase - m_shortBase));
        }

        public double GetHeight()
        {
            double x = GetRightSmallBase();
            return Math.Sqrt(Math.Pow(m_rightLeg,2.0) - Math.Pow(x,2.0));
        }

        public double GetSquare()
        {
            return GetHeight() * m_longBase / 2.0;
        }

        public double GetLeftBaseRadianAngle()
        {
            double sinX = GetHeight()/m_leftLeg;
            return Math.Round(Math.Asin(sinX),2);
        }

        public double GetRightBaseRadianAngle()
        {
            double x = GetRightSmallBase();
            double cosX = (Math.Pow(m_rightLeg,2.0) + Math.Pow(x,2.0) - Math.Pow(GetHeight(),2.0))/(2*x*m_rightLeg);
            return Math.Round(Math.Acos(cosX),2);
        }

        public double GetLeftBaseDegreeAngle()
        {
            double x = GetLeftBaseRadianAngle() * 180/ Math.PI;
            return Math.Round(x,2);
        }

        public double GetRightBaseDegreeAngle()
        {
            double x = GetRightBaseRadianAngle() * 180/ Math.PI;
            return Math.Round(x,2);
        }

        static void Main(string[] args)
        {
            MathTrapezoidSample trpz = new MathTrapezoidSample(20.0, 10.0, 8.0, 6.0);
            Console.WriteLine("The trapezoid's bases are 20.0 and 10.0, the trapezoid's legs are 8.0 and 6.0");
            double h = trpz.GetHeight();
            Console.WriteLine("Trapezoid height is: " + h.ToString());
            double dxR = trpz.GetLeftBaseRadianAngle();
            Console.WriteLine("Trapezoid left base angle is: " + dxR.ToString() + " Radians");
            double dyR = trpz.GetRightBaseRadianAngle();
            Console.WriteLine("Trapezoid right base angle is: " + dyR.ToString() + " Radians");
            double dxD = trpz.GetLeftBaseDegreeAngle();
            Console.WriteLine("Trapezoid left base angle is: " + dxD.ToString() + " Degrees");
            double dyD = trpz.GetRightBaseDegreeAngle();
            Console.WriteLine("Trapezoid left base angle is: " + dyD.ToString() + " Degrees");
        }
    }
}

open System

/// The following class represents simple functionality of the trapezoid.
type MathTrapezoidSample(longbase, shortbase, leftLeg, rightLeg) =
    member _.GetRightSmallBase() =
        (Math.Pow(rightLeg, 2.) - Math.Pow(leftLeg, 2.) + Math.Pow(longbase, 2.) + Math.Pow(shortbase, 2.) - 2. * shortbase * longbase) / (2. * (longbase - shortbase))

    member this.GetHeight() =
        let x = this.GetRightSmallBase()
        Math.Sqrt(Math.Pow(rightLeg, 2.) - Math.Pow(x, 2.))

    member this.GetSquare() =
        this.GetHeight() * longbase / 2.

    member this.GetLeftBaseRadianAngle() =
        let sinX = this.GetHeight() / leftLeg
        Math.Round(Math.Asin sinX,2)

    member this.GetRightBaseRadianAngle() =
        let x = this.GetRightSmallBase()
        let cosX = (Math.Pow(rightLeg, 2.) + Math.Pow(x, 2.) - Math.Pow(this.GetHeight(), 2.))/(2. * x * rightLeg)
        Math.Round(Math.Acos cosX, 2)

    member this.GetLeftBaseDegreeAngle() =
        let x = this.GetLeftBaseRadianAngle() * 180. / Math.PI
        Math.Round(x, 2)

    member this.GetRightBaseDegreeAngle() =
        let x = this.GetRightBaseRadianAngle() * 180. / Math.PI
        Math.Round(x, 2)

let trpz = MathTrapezoidSample(20., 10., 8., 6.)
printfn "The trapezoid's bases are 20.0 and 10.0, the trapezoid's legs are 8.0 and 6.0"
let h = trpz.GetHeight()
printfn $"Trapezoid height is: {h}"
let dxR = trpz.GetLeftBaseRadianAngle()
printfn $"Trapezoid left base angle is: {dxR} Radians"
let dyR = trpz.GetRightBaseRadianAngle()
printfn $"Trapezoid right base angle is: {dyR} Radians"
let dxD = trpz.GetLeftBaseDegreeAngle()
printfn $"Trapezoid left base angle is: {dxD} Degrees"
let dyD = trpz.GetRightBaseDegreeAngle()
printfn $"Trapezoid left base angle is: {dyD} Degrees"

'The following class represents simple functionality of the trapezoid.
Class MathTrapezoidSample

    Private m_longBase As Double
    Private m_shortBase As Double
    Private m_leftLeg As Double
    Private m_rightLeg As Double

    Public Sub New(ByVal longbase As Double, ByVal shortbase As Double, ByVal leftLeg As Double, ByVal rightLeg As Double)
        m_longBase = Math.Abs(longbase)
        m_shortBase = Math.Abs(shortbase)
        m_leftLeg = Math.Abs(leftLeg)
        m_rightLeg = Math.Abs(rightLeg)
    End Sub

    Private Function GetRightSmallBase() As Double
        GetRightSmallBase = (Math.Pow(m_rightLeg, 2) - Math.Pow(m_leftLeg, 2) + Math.Pow(m_longBase, 2) + Math.Pow(m_shortBase, 2) - 2 * m_shortBase * m_longBase) / (2 * (m_longBase - m_shortBase))
    End Function

    Public Function GetHeight() As Double
        Dim x As Double = GetRightSmallBase()
        GetHeight = Math.Sqrt(Math.Pow(m_rightLeg, 2) - Math.Pow(x, 2))
    End Function

    Public Function GetSquare() As Double
        GetSquare = GetHeight() * m_longBase / 2
    End Function

    Public Function GetLeftBaseRadianAngle() As Double
        Dim sinX As Double = GetHeight() / m_leftLeg
        GetLeftBaseRadianAngle = Math.Round(Math.Asin(sinX), 2)
    End Function

    Public Function GetRightBaseRadianAngle() As Double
        Dim x As Double = GetRightSmallBase()
        Dim cosX As Double = (Math.Pow(m_rightLeg, 2) + Math.Pow(x, 2) - Math.Pow(GetHeight(), 2)) / (2 * x * m_rightLeg)
        GetRightBaseRadianAngle = Math.Round(Math.Acos(cosX), 2)
    End Function

    Public Function GetLeftBaseDegreeAngle() As Double
        Dim x As Double = GetLeftBaseRadianAngle() * 180 / Math.PI
        GetLeftBaseDegreeAngle = Math.Round(x, 2)
    End Function

    Public Function GetRightBaseDegreeAngle() As Double
        Dim x As Double = GetRightBaseRadianAngle() * 180 / Math.PI
        GetRightBaseDegreeAngle = Math.Round(x, 2)
    End Function

    Public Shared Sub Main()
        Dim trpz As MathTrapezoidSample = New MathTrapezoidSample(20, 10, 8, 6)
        Console.WriteLine("The trapezoid's bases are 20.0 and 10.0, the trapezoid's legs are 8.0 and 6.0")
        Dim h As Double = trpz.GetHeight()
        Console.WriteLine("Trapezoid height is: " + h.ToString())
        Dim dxR As Double = trpz.GetLeftBaseRadianAngle()
        Console.WriteLine("Trapezoid left base angle is: " + dxR.ToString() + " Radians")
        Dim dyR As Double = trpz.GetRightBaseRadianAngle()
        Console.WriteLine("Trapezoid right base angle is: " + dyR.ToString() + " Radians")
        Dim dxD As Double = trpz.GetLeftBaseDegreeAngle()
        Console.WriteLine("Trapezoid left base angle is: " + dxD.ToString() + " Degrees")
        Dim dyD As Double = trpz.GetRightBaseDegreeAngle()
        Console.WriteLine("Trapezoid left base angle is: " + dyD.ToString() + " Degrees")
    End Sub
End Class

Remarks

A positive return value represents a counterclockwise angle from the x-axis; a negative return value represents a clockwise angle.

Multiply the return value by 180/Math.PI to convert from radians to degrees.

This method calls into the underlying C runtime, and the exact result or valid input range may differ between different operating systems or architectures.

Applies to

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