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MTH 111–112 Supplement

Section 1.1 Graph Transformations

Example 1.1.1.

The table below defines the functions \(f\text{,}\) \(g\text{,}\) and \(h\text{.}\) Express \(g(x)\) and \(h(x)\) in terms of \(f\text{.}\)
\(x\) \(-3\) \(-2\) \(-1\) \(0\) \(1\) \(2\) \(3\)
\(f(x)\) \(8\) \(6\) \(4\) \(2\) \(0\) \(-1\) \(-2\)
\(g(x)\) \(-8\) \(-6\) \(-4\) \(-2\) \(0\) \(1\) \(2\)
\(h(x)\) \(5\) \(3\) \(1\) \(1\) \(-3\) \(-4\) \(-5\)
Answer.
\(g(x)=-f(x)\) and \(h(x)=f(x)-3\text{.}\)

Example 1.1.2.

(a)

If \(f(x)=x^2\) and \(g(x)=2x^2+5\text{,}\) express \(g(x)\) in terms of \(f\text{.}\)
Answer.
\(g(x)=2f(x)+5\)

(b)

If \(f(x)=x^2\) and \(h(x)=(x+5)^2-3\text{,}\) express \(h(x)\) in terms of \(f\text{.}\)
Answer.
\(h(x)=f(x+5)-3\)

Exercises Exercises

One Function in Terms of Another.

In Exercises 1–4, the table below defines the functions \(f\text{,}\) \(g\text{,}\) \(h\text{,}\) \(k\text{,}\) and \(l\text{.}\)
\(x\) \(-2\) \(-1\) \(0\) \(1\) \(2\)
\(f(x)\) \(0\) \(1\) \(2\) \(3\) \(4\)
\(g(x)\) \(4\) \(3\) \(2\) \(1\) \(0\)
\(h(x)\) \(0\) \(-1\) \(-2\) \(-3\) \(-4\)
\(k(x)\) \(6\) \(7\) \(8\) \(9\) \(10\)
\(l(x)\) \(0\) \(3\) \(6\) \(9\) \(12\)
1.
Express \(g(x)\) in terms of \(f\) and describe how the graph of \(y=f(x)\) can be transformed into the graph of \(y=g(x)\text{.}\)
2.
Express \(h(x)\) in terms of \(f\) and describe how the graph of \(y=f(x)\) can be transformed into the graph of \(y=h(x)\text{.}\)
3.
Express \(k(x)\) in terms of \(f\) and describe how the graph of \(y=f(x)\) can be transformed into the graph of \(y=k(x)\text{.}\)
4.
Express \(l(x)\) in terms of \(f\) and describe how the graph of \(y=f(x)\) can be transformed into the graph of \(y=l(x)\text{.}\)

5.

The second row in the table below gives values for the function \(f\text{.}\) Complete the rest of the table. If you don’t have sufficient information to fill in some of the cells, leave those cells blank.
\(x\) \(-4\) \(-3\) \(-2\) \(-1\) \(0\) \(1\) \(2\) \(3\) \(4\)
\(f(x)\) \(-2\) \(-1\) \(0\) \(1\) \(2\) \(3\) \(4\) \(5\) \(6\)
\(\frac{1}{2}x\)
\(-2f(x)\)
\(f(x)+5\)
\(f(x+2)\)
\(f\mathopen{}\left( \frac{1}{2}x \right)\mathclose{}\)
\(f(2x)\)
\(f(x-3)\) \(\phantom{-0}\) \(\phantom{-0}\) \(\phantom{-0}\) \(\phantom{-0}\) \(\phantom{-0}\) \(\phantom{-0}\) \(\phantom{-0}\) \(\phantom{-0}\) \(\phantom{-0}\)

Find the Transformations.

In Exercises 6–9, first write \(g(x)\) in terms of \(f\text{.}\) Then compose a sequence of transformations that will transform the graph of \(y=f(x)\) into the graph of \(y=g(x)\text{.}\)
6.
\(f(x)=\sqrt{x}\qquad g(x)=\frac{\sqrt{x-7}}{4}\)
7.
\(f(x)=\frac{1}{x}\qquad g(x)=\frac{2}{x}+3\)
8.
\(f(x)=x^2\qquad g(x)=-4\mathopen{}\left( \frac{1}{2}x-5 \right)^2\mathclose{}+3\)
9.
\(f(x)=\sqrt[3]{x}\qquad g(x)=\frac{1}{2}\sqrt[3]{10x+30}-6\)

Sketch Transformations.

In Exercises 10–13, use the provided graph of \(y=f(x)\) to sketch a graph of each given function.
The graph of f of x which is shown has the points (-4,4), (-2, 0), (0, 4), (2, 4), (4, -4) all connected.
10.
\(k_1(x)=f(2x)\)
A blank graph.
11.
\(k_2(x)=2f(-2x)-1\)
A blank graph.
12.
\(k_3(x)=-2f(2x+4)\)
A blank graph.
13.
\(k_4(x)=f\mathopen{}\left(\frac{1}{2}x\right)\mathclose{} +2\)
A blank graph.