org.josef.science.math

Class QuadraticEquation

java.lang.Object

org.josef.science.math.QuadraticEquation

@Status(stage=PRODUCTION,
        unitTests=COMPLETE)
 @Review(by="Kees Schotanus",
        at="2009-11-21",
        reason="Initial review")
 @ThreadSafety(level=IMMUTABLE)
public final class QuadraticEquation
extends Object

Represents a Quadratic Equation that is solved by using the Quadratic Formula.
The Quadratic formula can solve quadratic equations that are mathematically expressed as: ax² + bx + c = 0
The quadratic formula is expressed as: (-b ± √(b² -4ac)) / 2a
b² - 4ac is called the Discriminant (D).

Discriminant	Roots
Negative	Two complex solutions
Zero	One (repeated) real solution
Positive	Two real solutions

Version:

1.0 $Revision: 6488 $

Author:

Kees Schotanus

Constructor Summary

Constructors

Constructor and Description
QuadraticEquation(double a, double b, double c) Creates this QuadraticEquation from the supplied a, b and c.

Method Summary

Modifier and Type	Method and Description
Complex[]	getComplexRoots() Gets the Complex roots.
double	getDiscriminant() Gets the Discriminant.
int	getNumberOfRoots() Gets the number of roots of this quadratic equation.
double[]	getRealRoots() Gets the real roots.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

QuadraticEquation

public QuadraticEquation(double a,
                         double b,
                         double c)

Creates this QuadraticEquation from the supplied a, b and c.

Parameters:

a - The value of the quadratic coefficient.
This value may not be 0.0D. When this would be allowed we would divide by zero. Furthermore, the equation would not be quadratic.

b - The value of the linear coefficient.

c - The value of the constant term.

Method Detail

getDiscriminant

public double getDiscriminant()

Gets the Discriminant.
The discriminant is defined as: b² - 4ac

Returns:

The discriminant.

getNumberOfRoots

public int getNumberOfRoots()

Gets the number of roots of this quadratic equation.

Returns:

The number of roots of this quadratic equation.
A quadratic equation has either 1 or 2 roots.

getRealRoots

public double[] getRealRoots()

Gets the real roots.

Returns:

The real roots.

Throws:

ArithmeticException - When no real roots exist.

getComplexRoots

public Complex[] getComplexRoots()

Gets the Complex roots.

Returns:

The Complex roots.

Throws:

ArithmeticException - When no Complex roots exist.