Export (0) Print
Expand All

Math.Acos Method

Returns the angle whose cosine is the specified number.

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

public static double Acos (
	double d
)
public static double Acos (
	double d
)
public static function Acos (
	d : double
) : double

Parameters

d

A number representing a cosine, where -1 d 1.

Return Value

An angle, θ, measured in radians, such that 0 θπ -or- NaN if d < -1 or d > 1.

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

The following code sample uses Acos to assist in the computation of the inner angles of a given trapezoid.

/// <summary>
/// The following class represents simple functionallity of the Trapezoid
/// </summary>
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 trpezoid'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");
    }
}

/// <summary>
/// The following class represents simple functionallity of the Trapezoid
/// </summary>
class MathTrapezoidSample
{
    private double mLongBase;
    private double mShortBase;
    private double mLeftLeg;
    private double mRightLeg;
    public MathTrapezoidSample(double longBase, double shortBase, 
        double leftLeg, double rightLeg)
    {
        mLongBase = System.Math.Abs(longBase);
        mShortBase = System.Math.Abs(shortBase);
        mLeftLeg = System.Math.Abs(leftLeg);
        mRightLeg = System.Math.Abs(rightLeg);
    } //MathTrapezoidSample

    private double GetRightSmallBase()
    {
        return (System.Math.Pow(mRightLeg, 2.0) 
            - System.Math.Pow(mLeftLeg, 2.0) 
            + System.Math.Pow(mLongBase, 2.0) 
            + System.Math.Pow(mShortBase, 2.0) 
            - 2 * mShortBase * mLongBase) / (2 * (mLongBase - mShortBase));
    } //GetRightSmallBase

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

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

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

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

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

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

    public static void main(String[] args)
    {
        MathTrapezoidSample trpz = 
            new MathTrapezoidSample(20.0, 10.0, 8.0, 6.0);
        Console.WriteLine("The trpezoid'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: " 
            + System.Convert.ToString(h));
        double dxR = trpz.GetLeftBaseRadianAngle();
        Console.WriteLine("Trapezoid left base angle is: " 
            + System.Convert.ToString(dxR) + " Radians");
        double dyR = trpz.GetRightBaseRadianAngle();
        Console.WriteLine("Trapezoid right base angle is: " 
            + System.Convert.ToString(dyR) + " Radians");
        double dxD = trpz.GetLeftBaseDegreeAngle();
        Console.WriteLine("Trapezoid left base angle is: " 
            + System.Convert.ToString(dxD) + " Degrees");
        double dyD = trpz.GetRightBaseDegreeAngle();
        Console.WriteLine("Trapezoid left base angle is: " 
            + System.Convert.ToString(dyD) + " Degrees");
    } //main
} //MathTrapezoidSample

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

Community Additions

ADD
Show:
© 2014 Microsoft