Pearson Algebra 1 Common Core, 2011
PA
Pearson Algebra 1 Common Core, 2011 View details
7. Graphing Rational Functions
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Exercise 33 Page 711

Practice makes perfect
a

We want to graph the rational functions y= 1x and y= 1x^2. To do so we will first make a table of values. Then we will use those points to identify the shape of the graphs.

y_1=1/x y_2=1/x^2
x 1/x (x,y) 1/x^2 (x,y)
- 4 1/- 4 ( - 4, - 0.25) 1/( - 4)^2 ( -4, 0.06)
- 2 1/- 2 ( - 2, - 0.5) 1/( - 2)^2 ( -2, 0.25)
- 1 1/- 1 ( - 1, - 1) 1/( - 1)^2 ( -1, -1)
- 0.5 1/- 0.5 ( - 0.5, -2) 1/( -0.5)^2 ( - 0.5, 4)
0 1/0 undefined 1/0^2 undefined
0.5 1/0.5 ( 0.5, 2) 1/( 0.5)^2 ( 0.5, 4)
1 1/1 ( 1, 1) 1/1^2 ( 1, 1)
2 1/2 ( 1, 0.5) 1/2^2 ( 1, 0.25)
4 1/4 ( 4, 0.25) 1/4^2 ( 4, 0.06)

Let's plot these points and connect them with a smooth curve for each function.

GRAPHS




b

We are asked to find the vertical and horizontal asymptotes of the functions that we graphed in Part A. Let's take a look at them, considering the lines that the graphs approach.

GRAPHS

As we can see, both of the graphs get closer to the y-axis as the x-values get closer to 0, and they get closer to the x-axis as the x-values get larger in absolute value. Therefore, the vertical asymptote of the graphs is the line x=0 and the horizontal asymptote is y=0.

c

We want to find the range of y= 1x and y= 1x^2. Let's remember that the range of a function is the set of all possible y-values. When we consider the graphs that we drew in Part A and B, we can see that the range of y= 1x is all real numbers except zero, and the range of y= 1x^2 is all real numbers greater than zero.