Module 3 Summary

 

In this module you investigated the following question: How can the ability to graph and analyze polynomial functions be used in graphic design?

 

In Module 3 Project: Graphic Design Using Polynomials, you looked at how you could use polynomial functions to model curves found in images and how the factors of the polynomial relate to the curve.

 

Two different, yet mathematically equivalent, forms of polynomial functions can be used to determine

The following table summarizes the key ideas of the module.

 

Lesson 1 The end behaviour of a polynomial function can be determined by the degree and sign of the leading coefficient.

Odd-Degree, Positive-Leading Coefficient

 

This shows the graphs of g(x) = x and f(x) = 2x cubed + 6x squared – 7.

 

Odd-Degree, Negative-Leading Coefficient

 

This shows the graphs of g(x) = –x and f(x) = –4x cubed + 8x squared + x + 1.

 

 

Even-Degree, Positive-Leading Coefficient

 

This shows the graphs of g(x) = x squared and f(x) = 0.8x to the fourth + 4xcubed + 2.5x squared – x – 3.

 

 

Even-Degree, Negative-Leading Coefficient

 

This shows the graphs of g(x) = –x2 and f(x) = –x to the power of 4 + 2x to the power of 3 + 3x squared – 2x + 6.

  The x-intercepts of a polynomial function can be determined by looking at the factors of the polynomial. This shows the graph of f of x = 0.9(x – 3)(x – 3)(x + 2). An arrow pointing to “(x – 3)(x – 3)” has the caption “Even multiplicity; graph touches but does not cross x-axis at x = 3.” An arrow pointing to “(x + 2)” has the caption “odd multiplicity; graph crosses x-axis at x = –2.”
Lesson 2

You can perform long division on polynomials like you can with numbers.

 

Polynomials can be factored using

  • the remainder theorem: (f(a) = the remainder when f(x) is divided by xa)
  • the factor theorem: look for values of a such that f(a) = 0
  • the integral zero theorem: try factors of the constant term of f(x);18 in the example shown
This shows the function f of x = x cubed – 4x squared – 3x + 18 with an arrow going to the function f of x = (x – 3)(x – 3)(x + 2).
Lesson 3 Polynomial equations can be solved by factoring polynomials and using the zero-product property. This shows the equation (x – 3)(x – 3)(x + 2) = 0. An arrow goes from the first (x – 3) to x = 3. An arrow goes from the second (x – 3) to another x = 3. An arrow goes from (x + 2) to x = –2.