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Piecewise Functions 1. Friday, April 26th. Warm Up. Graph the following equations by hand on this graph!! 1) f(x) = x + 3 2) f(x) = 2x – 1 3) f(x)= x 2. What is a piecewise function?. A function that uses different equations for different parts of its domain.
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Piecewise Functions 1 Friday, April 26th
Warm Up • Graph the following equations by hand on this graph!! 1) f(x) = x + 3 2) f(x) = 2x – 1 3) f(x)= x2
What is a piecewise function? • A function that uses different equations for different parts of its domain. • Basically, a bunch of functions put together in pieces!
We look at only one piece! Original Piecewise
Graphing with one piece • Step 1: Graph the original • Step 2: Put a line (“fence”) on the domain restriction For example here, x = 2 • Step 3: Greater or Less than? Erase the part you do not need! Since x is less than 2 (we want this piece!), Erase the part greater than 2, we don’t want that part! • Step 4: Filled in circle or open at x=2? • Fill in when you have an equal to sign!
Graphing with one piece • Step 1: Graph the original • Step 2: Put a line on the domain restriction For example here, x = -3 • Step 3: Greater or Less than? Erase the part you do not need! Since x is greater than -3 (we want this piece!), Erase the part less than -3, we don’t want that part! • Step 4: Filled in circle or open at x= -3? • Fill in when you have an equal to sign!
Graphing with one piece • Step 1: Graph the original • Step 2: Put a line on the domain restrictions-two now! For example, put up two “fences” at -1 and at 5! • Step 3: Now x is in between two numbers! Since x is between -1 & 5 (we want this piece!), Erase the parts outside of those two numbers, we don’t want that part! • Step 4: Filled in circle or open at x = -1 and x = 5? • Fill in when you have an equal to sign! Who owns the fence?
Once you get the hang of it you do not have to graph & erase—you can just graph the part you need! You Try! DO the steps! • Step 1: Graph the original • Step 2: Put a line on the domain restriction For example here, x = 4 • Step 3: Greater or Less than? Erase the part you do not need! Since x is less than 4 (we want this piece!), Erase the part greater than 4, we don’t want that part! • Step 4: Filled in circle or open at x = 4? • Fill in when you have an equal to sign!
You Try! DO the steps! • Step 1: Graph the original • Step 2: Put up “fences” on the domain restrictions For example here, x = -2, 4 • Step 3: Step 3: Now x is in between two numbers! Since x is between -2 & 4 (we want this piece!), Erase the parts outside of those two numbers, we don’t want that part! • Step 4: Filled in circle or open at x = -2 & 4? • Fill in when you have an equal to sign! Who owns the fence?
Graphing with TWO pieces This works the same way, you just go through the steps twice!
Graphing with TWO pieces This works the same way, you just go through the steps twice!
What about evaluating? • How would you find the following? • f(-4) = • f(-3) = • f(1) =
You Try! Do the steps twice! This works the same way, you just go through the steps twice! f(5) = f(3)= f(-1)=
You Try! Do the steps twice! This works the same way, you just go through the steps twice! f(6) = f(-3)= f(2)=
Homework • Worksheet
Piecewise Functions 2 April 26th, 2013
Remember… • What is a piecewise function? • How do we graph them? • Which equation do we plug certain x-values in to?
Review: Graphing with one piece • Step 1: Graph the original FILL IN THE TABLE! • Step 2: Put a line (“fence”) on the domain restriction For example here, x = 2 • Step 3: Greater or Less than? Erase the part you do not need! Since x is less than 2 (we want this piece!), Erase the part greater than 2, we don’t want that part! • Step 4: Filled in circle or open at x=2? • Fill in when you have an equal to sign!
What values should we put in our table? • Now that we have learned how to graph, lets take some short cuts! • Look at the domain restrictions, ONLY make your table for the values you NEED. • Look to see if there is an “equal to” to see if you should include that number. • Then we won’t need to erase, this will help graph faster!
What if there is one table for two pieces? • Look at the domain restrictions, figure out which numbers from the table should be used for the first equation, and which numbers should be used for the second. • Find the “equal to” to see which equation you should use for that specific number.
Graphing with TWO pieces Which equation should I use for the x values -2 to 0? 1 to 3?
Graphing with TWO pieces Which equation should I use for the x values -5 to -4? -3 to 0?
Graphing with TWO pieces Which equation should I use for the x values -3 to -1? 0 to 5?
You Try with TWO pieces Which equation should I use for the x values -1 to 2? 3 to 4?
You Try with TWO pieces Which equation should I use for the x values -4 to -2? -1 to 1?
Activity • Finish/Start Greeting Card Activity • Work with a partner to complete the activity. Write your answers/solutions neatly. • Each pair will present one question to the class.
Homework • Worksheet # 2