Lesson 4

1. Lesson 4

Mathematics 30-1 Module 7

Module 7: Rational Functions and Function Operations

Lesson 4: Adding and Subtracting Functions

Focus

This is a photo of a wallet on top of a 100 dollar bill. Lower in the photo are three keys from a keyboard that spell out the word “tax.”

Hemera/Thinkstock

Pumping gas, travelling a toll road, buying a car, using an airport: tax is everywhere and must be calculated into the cost of transportation. The Goods and Services Tax, or GST, is a visible tax in Canada. When you purchase most goods or services in Canada, you have to pay for the item or service as well as the GST. Do you calculate the tax on something you buy in one or two steps? Is it possible to give a rule that explains how any percentage tax can be calculated? Can you think of a rule that shows the change in the amount paid if the tax rate changes?

In this lesson you will explore how multiple functions can be combined using addition or subtraction.

Lesson Outcomes

At the end of this lesson you will be able to

add and subtract functions
determine the domain and range of the sum or difference of functions

Lesson Question

You will investigate the following question:

How can functions be added or subtracted?

Assessment

Your assessment may be based on a combination of the following tasks:

completion of the Lesson 4 Assignment (Download the Lesson 4 Assignment and save it in your course folder now.)
course folder submissions from Try This and Share activities
additions to Formula Sheet