Big Ideas Math Algebra 2, 2014
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Big Ideas Math Algebra 2, 2014 View details
2. Graphing Rational Functions
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Exercise 8 Page 368

Start by dividing the numerator by the denominator.

Function: g(x)=1/x+1+2
Graph:

Graph of g as a Transformation of the Graph of f(x)= ax: Translation 1 unit left and 2 units up of the graph of f(x)= 1x.

Practice makes perfect

We will rewrite the function, describe the graph of g as a transformation of the graph of f(x)= ax, and draw the graph of g.

Rewriting the Function

We want to rewrite the given rational function so that it is in the form g(x)= ax-h+k. To do so, we will start by dividing the numerator of the function by the denominator.
l r x + 1 & |l 2x+3
â–Ľ
Divide

2x/x= 2

r 2 r x+1 & |l 2x+3

Multiply term by divisor

r 2 rl x+1 & |l 2x+3 & 2x+2

Subtract down

r 2 r x+1 & |l 1

The quotient is 2 with a remainder of 1. We can rewrite the function using this information. g(x)=2x+3/x+1 ⇔ g(x)=1/x+1+ 2

Describing the Graph as a Transformation of f(x)= ax and Graphing

Let's start by recalling two possible transformations of the function f(x)= ax.

Function Transformation of the Graph of f(x)= ax
g(x)=a/x- h Horizontal translation by h units.
If h>0, the translation is to the right.
If h<0, the translation is to the left.
g(x)=a/x+ k Vertical translation by k units.
If k>0, the translation is up.
If k<0, the translation is down.

Now consider the obtained equation. g(x)=1/x+1+2 ⇔ g(x)=1/x-( - 1)+ 2 We can see that a= 1, h= - 1, and k= 2. Therefore, the graph of g is a translation 1 unit left and 2 units up of the graph of f(x)= 1x. We will use this information to draw the graph.