becker.xtras.grapher
Interface IQuadraticFunction

public interface IQuadraticFunction

A quadratic function, f(x), has the form ax² + bx¹ + cx⁰, or more simply, ax² + bx + c where the coefficients a, b, and c are real numbers.

For example, if a=2.0, b=4.0, and c=1.0 then f(x) = 2.0*x² + 4.0*x + 1.0. The function may be evaluated for a particular value of x by substituting the value for x in the above equation. For example, f(2) = 2.0*2² + 4.0*2 + 1.0 = 2.0*4 + 8.0 + 1.0 = 17.0.

A class implementing the IQuadraticFunction interface will be able to evaluate a function at a particular value of x using the eval method. The current values of a, b and c can be obtained with getA, getB, and getC. Finally, the coefficients can be reset to represent a new function with setCoefficients.

The function can be graphed by passing an instance of IQuadraticFunction to GrapherGUI. Please see the package description for a more in-depth discussion of using this class.

Author:

Byron Weber Becker

See Also:

IFunction, IPolynomialFunction, GrapherGUI

Method Summary

void	addView(IView aView) Add a view (graphical user interface) to the function.
double	eval(double x) Evaluate the function for a given value of x.
double	getA() Get the current value of coefficient a
double	getB() Get the current value of coefficient b
double	getC() Get the current value of coefficient c
void	setCoefficients(double a, double b, double c) Set the coefficients of the quadratic function, a, b, and c to new values.

Method Detail

getA

double getA()

Get the current value of coefficient a

Returns:

the coefficient for the x² term.

getB

double getB()

Get the current value of coefficient b

Returns:

the coefficient for the x¹ term.

getC

double getC()

Get the current value of coefficient c

Returns:

the coefficient for the x⁰ term.

setCoefficients

void setCoefficients(double a,
                     double b,
                     double c)

Set the coefficients of the quadratic function, a, b, and c to new values.

Parameters:

a - The new coeffient for the x² term.

b - The new coeffient for the x¹ term.

c - The new coeffient for the x⁰ term.

eval

double eval(double x)

Evaluate the function for a given value of x.

Parameters:

x - The value for which the function should be evaluated.

addView

void addView(IView aView)

Add a view (graphical user interface) to the function. The view's updateView method must be called each time the function's state changes.