Co n cep t Byt e
Use W ith Lesson 11 -7@ C om m on C ore State S tandards
^ mm L||««« A-CED.A.2 Creat e equations in two or more variables
I K/ 1 1 1 1 1 x j l \ U 1111 U I t o r ep resen t rel at i o n sh ip s b et w een q u an t i t i es; g raphFu n ct i o n s
eq uations on coordinate axes wit h labels and scales.
MP 5Functions such as y = y = —and y = 4 - 4 are examples of rational
functions. When you use a graphing calculator to graph a rational function, false
connections may appear on the screen. When this happens, you need to make
adjustments to see the true shape of the graph.Graph the function y = - 4. You can enter this as y = 1 -s- (x + 2) - 4. The
graph on your screen may look like the one at the right. The highest point and the
lowest point on the graph that appear on the screen are not supposed to connect. If
you use the jygjgj key on the calculator, you can see that no point on the graph lies on
this connecting line. So this is a false connection.MAIHEMATICAL
PRACTICESHere’s how you can graph a rational function and avoid false connections.St e p 2Fa l se
connectionVI
St e p 1 Press the key. Then
scroll down and right to
highlight the word DOT.
Then press.Graph the function
7 = 7+1 ~ 4 a 8 ain-
Now the false connection
is gone.St e p 3 Use the key or
TABLE feature to find
some points on the graph.
Sketch the graph.Sci En g
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Degree
Par Pol Seq
Co n n ected l i B i
Si m u l
reA6i
G- T
\ >Ex e r c i se s
Use a graphing calculator to graph each function. Then sketch the graph.
j 1
1-7 = 1 3-7 = 7T2- y = y + 2
2-7=-I
1 _
6 -7 = x 7.y = F LT + 24.7 = ^8-7x- 4
3
x- 2-4- a. Graphy = i 7 = andy =
b. Make a Conjecture How does adding or subtracting a positive number in the
denominator of y = \ translate the graph? - a. Graph y = y = \ - 4, and y = \ + 3.
b. Make a Conjecture How does adding or subtracting a positive number on the
right side of y = \ translate the graph?
t
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