Piecewise Functions

Warm Up

1. What did you think of the test yesterday?2. What topic(s) do you think you need the

most practice/review of before the midterm?3. Solve the following equation for y: ax + (by)2

= c4. Write down everything you can think of

when you hear “piecewise function.”5. Solve the following equation: log5x + 2log5

= log60

Announcements

If you did not finish your test yesterday, you have until this afternoon after school to finish it.

If you still have not made up your quiz from last Monday, TODAY IS YOUR ABSOLUTE LAST DAY TO DO IT. Those people are: 2nd: Faith Gowl, Brenda Leon, Joey Rebol 3rd: Zach James

Calendar for next few days (2nd block)

15Unit 4 Test

16Intro to piecewise functions

17PSATReview for Midterm

18Applications of piecewise functions

19Review for Midterm

22Review for Midterm

23Midterm

Calendar for next few days (3rd block)

15Unit 4 Test

16Intro to piecewise functions

17PSATReview for Midterm

18Review for Midterm

19Review for Midterm

22Midterm

23Applications of piecewise functions

Today’s Objectives

SWBAT graph piecewise functions.SWBAT evaluate piecewise functions for

given domain values.SWBAT identify points of discontinuity and

state whether piecewise functions are continuous or not.

Piecewise FunctionsWhat are they and why do we need them?

Functions that have different rules for different domain values.

They are made up of 2 or more “normal” functions.

Piecewise FunctionsWhat are they and why do we need them?

They help us represent situations where rates are different at different points in time.

(ex) If you are driving a car at 60 mph for the first three hours, then you stop for an hour to eat lunch, then you drive 80 mph for the next four hours. The function would look like this:

Can you draw 3 graphs to represent these situations?

Saundra is a personal trainer at a local gym. Earlier this year, three of her clients asked her to help them train for an upcoming 5K race. Though Saundra had never trained someone for a race, she developed plans for each of her clients that she believed would help them perform their best.

She wanted to see if her plans were effective, so when she attended the race to cheer them on, she collected data at regular intervals along the race. Her plan was to create graphs for each of the runners and compare their performances. Since each had an individualized strategy, each runner ran a different plan during the race.

One of her clients (Sue, the oldest one), was supposed to begin slowly, increasing over the first kilometer until she hit a speed which she believed she could maintain over the rest of the race.

Her second client, Jim, was supposed to begin with a strong burst for the first kilometer, then slow to a steady pace until the final kilometer when he would finish with a strong burst.

Her third client, Jason, is a very experienced runner. His plan was to run at a steady pace for the first two kilometers, then run at his maximum speed for the final 3 kilometers.

Sue’s graph

One of her clients (Sue, the oldest one), was supposed to begin slowly, increasing over the first kilometer until she hit a speed which she believed she could maintain over the rest of the race.

Jim’s graph

Her second client, Jim, was supposed to begin with a strong burst for the first kilometer, then slow to a steady pace until the final kilometer when he would finish with a strong burst.

Jason’s graph

Her third client, Jason, is a very experienced runner. His plan was to run at a steady pace for the first two kilometers, then run at his maximum speed for the final 3 kilometers.

Evaluate a piecewise function at specified points of the domain

Example:

You Try two.

f(8) =

Continuous or discontinuous?

A piecewise function is continuous if: its functions touch at their meeting points AND if it is defined for all values of x.

To determine whether or not it is continuous: 1. Look to make sure ALL REAL NUMBERS are

included in the domain. 2. Evaluate all functions at the end points to see if

both functions give the same value. 3. If your piecewise function passes BOTH of the

above tests, then it is continuous.

Continuous or discontinuous?

Example:

You try two:

Graph a piecewise function

Graph a piecewise function

Graph a piecewise function.

Example

You Try the next two.

Identify points of discontinuity given a graph.

When we are given a graph, we can tell if and where the piecewise function is discontinuous, just by looking at the graph:

You try 3.

Complete the practice worksheet with a partner.

Find 1 partner you would like to work with.Work with your partner to finish the class

work sheet.You must work TOGETHER.The first pair with all problems done

correctly earns a small prize. Completing this sheet thoroughly earns you

your class work stamp for today.

Homework

Half worksheet – all problems.

Presentations

Groups that did not complete their presentations on Thursday will complete them today to finish class