Chapter 3

Contemporary Precalculus · 261 exercises

Problem 22

Use algebra to find the inverse of the given one-to-one function. $$f(x)=\sqrt[5]{\frac{3 x-1}{x-2}}$$

4 step solution

Problem 22

Compute and simplify the difference quotient of the function. $$f(t)=160,000-8000 t+t^{2}$$

6 step solution

Problem 22

Describe a sequence of transformations that will transform the graph of the function \(f\) into the graph of the function \(g.\) $$f(x)=x^{2}+x ; \quad g(x)=(x-3)^{2}+(x-3)+2$$

3 step solution

Problem 22

Find the rule of the function \(f \circ g,\) the domain of \(f \circ g,\) the rule of \(g \cdot f,\) and the domain of \(g \circ f\) $$f(x)=1 / x, \quad g(x)=\sqrt{x}$$

4 step solution

Problem 22

(a) Use the fact that the absolute value function is piecewise-defined (see Example 7) to write the rule of the given function as a piecewise-defined function whose rule does not include any absolute value bars. (b) Graph the function. $$g(x)=|x|-4$$

3 step solution

Problem 22

Each equation defines y as a function of \(x .\) Create a table that shows the values of the function for the given values of \(x\) $$y=x^{10}-100 x \quad x=-1,0,1,2,3,4$$

3 step solution

Problem 23

Use the Round-Trip Theorem on page 223 to show that \(g\) is the inverse of \(f\) $$f(x)=x+1, \quad g(x)=x-1$$

5 step solution

Problem 23

Compute and simplify the difference quotient of the function. $$V(x)=x^{3}$$

5 step solution

Problem 23

Describe a sequence of transformations that will transform the graph of the function \(f\) into the graph of the function \(g.\) $$f(x)=x^{2}+5 ; \quad g(x)=(x+2)^{2}+10$$

3 step solution

Problem 23

Find the rule of the function \(f \circ g,\) the domain of \(f \circ g,\) the rule of \(g \cdot f,\) and the domain of \(g \circ f\) $$f(x)=\frac{1}{2 x+1}, \quad g(x)=x^{2}-1$$

4 step solution

Problem 23

Refer to these three functions: $$ \begin{aligned} f(x) &=\sqrt{x+3}-x+1 \\ g(t) &=t^{2}-1 \\ h(x) &=x^{2}+\frac{1}{x}+2 \end{aligned} $$ In each case, find the indicated value of the function. $$f(g(3))$$

2 step solution

Problem 24

Use the Round-Trip Theorem on page 223 to show that \(g\) is the inverse of \(f\) $$f(x)=2 x-6, \quad g(x)=\frac{x}{2}+3$$

7 step solution

Problem 24

Describe a sequence of transformations that will transform the graph of the function \(f\) into the graph of the function \(g.\) $$f(x)=\sqrt{x^{3}+5} ; \quad g(x)=-\frac{1}{2} \sqrt{x^{3}+5}-6$$

3 step solution

Problem 24

Compute and simplify the difference quotient of the function. $$A(r)=\pi r^{2}$$

2 step solution

Problem 24

(a) Use the fact that the absolute value function is piecewise-defined (see Example 7) to write the rule of the given function as a piecewise-defined function whose rule does not include any absolute value bars. (b) Graph the function. $$g(x)=|x+3|$$

2 step solution

Problem 25

Describe a sequence of transformations that will transform the graph of the function \(f\) into the graph of the function \(g.\) $$f(x)=\sqrt{x^{4}+x^{2}+1} ; g(x)=10-\sqrt{4 x^{4}+4 x^{2}+4}$$

5 step solution

Problem 25

Find the rules of the functions ff and \(f \circ f\) $$f(x)=x^{3}$$

4 step solution

Problem 25

Show that the function \(f(x)=|x|+|x-2|\) is constant on the interval \([0,2] .\) [ Hint: Use the definition of absolute value (see Example \(7 \text { ) to compute } f(x) \text { when } 0 \leq x \leq 2 .]\)

6 step solution

Problem 25

Assume \(h \neq 0 .\) Compute and simplify the difference quotient $$ \frac{f(x+h)-f(x)}{h} $$ $$f(x)=x+1$$

5 step solution

Problem 26

Use the Round-Trip Theorem on page 223 to show that \(g\) is the inverse of \(f\) $$f(x)=\frac{-3}{2 x+5}, \quad g(x)=\frac{-3-5 x}{2 x}$$

5 step solution

Problem 26

Write the rule of a function g whose graph can be obtained from the graph of the function \(f\) by performing the transformations in the order given. \(f(x)=x^{2}+2 ;\) shift the graph horizontally 5 units to the left and then vertically upward 4 units.

3 step solution

Problem 26

Find the rules of the functions ff and \(f \circ f\) $$f(x)=(x-1)^{2}$$

3 step solution

Problem 26

Find the approximate location of all local maxima and minima of the function. $$f(x)=x^{3}-x$$

4 step solution

Problem 26

Assume \(h \neq 0 .\) Compute and simplify the difference quotient $$ \frac{f(x+h)-f(x)}{h} $$ $$f(x)=-10 x$$

3 step solution

Problem 27

Use the Round-Trip Theorem on page 223 to show that \(g\) is the inverse of \(f\) $$f(x)=x^{5}, \quad g(x)=\sqrt[5]{x}$$

4 step solution

Problem 27

Write the rule of a function g whose graph can be obtained from the graph of the function \(f\) by performing the transformations in the order given. \(f(x)=x^{2}-x+1 ;\) reflect the graph in the \(x\) -axis, then shift it vertically upward 3 units.

2 step solution

Problem 27

Find the rules of the functions ff and \(f \circ f\) $$f(x)=1 / x$$

5 step solution

Problem 27

Find the approximate location of all local maxima and minima of the function. $$g(t)=-\sqrt{16-t^{2}}$$

4 step solution

Problem 27

Assume \(h \neq 0 .\) Compute and simplify the difference quotient $$ \frac{f(x+h)-f(x)}{h} $$ $$f(x)=3 x+7$$

4 step solution

Problem 27

The amount of postage required to mail a first-class letter is determined by its weight. In this situation, is weight a function of postage? Or vice versa? Or both?

4 step solution

Problem 28

Use the Round-Trip Theorem on page 223 to show that \(g\) is the inverse of \(f\) $$f(x)=x^{3}-1, \quad g(x)=\sqrt[3]{x+1}$$

2 step solution

Problem 28

Write the rule of a function g whose graph can be obtained from the graph of the function \(f\) by performing the transformations in the order given. \(f(x)=\sqrt{x} ;\) shift the graph horizontally 6 units to the right, stretch it away from the \(x\) -axis by a factor of \(2,\) and shift it vertically downward 3 units.

3 step solution

Problem 28

Find the approximate location of all local maxima and minima of the function. $$h(x)=\frac{x}{x^{2}+1}$$

4 step solution

Problem 28

Assume \(h \neq 0 .\) Compute and simplify the difference quotient $$ \frac{f(x+h)-f(x)}{h} $$ $$f(x)=x^{2}$$

5 step solution

Problem 28

Chinese philosopher Laotze (600 BC) said, "the farther one travels, the less one knows." Let \(x\) be the distance one travels, and \(y\) be the amount one knows. If Laotze is right, is \(y\) a function of \(x ?\) Is \(x\) a function of \(y ?\) Why or Why not?

5 step solution

Problem 29

Show that the inverse function of the function \(f\) whose rule is \(f(x)=\frac{2 x+1}{3 x-2}\) is \(f\) itself.

4 step solution

Problem 29

Write the rule of a function g whose graph can be obtained from the graph of the function \(f\) by performing the transformations in the order given. \(f(x)=\sqrt{-x} ;\) shift the graph horizontally 3 units to the left, then reflect it in the \(x\) -axis, and shrink it toward the \(x\) -axis by a factor of \(1 / 2\).

3 step solution

Problem 29

Verify that \((f \circ g)(x)=x\) and \((g \circ f)(x)=x\) for every \(x\) $$f(x)=9 x+8, \quad g(x)=\frac{x-8}{9}$$

4 step solution

Problem 29

Find the approximate location of all local maxima and minima of the function. $$k(x)=x^{3}-3 x+1$$

5 step solution

Problem 29

Assume \(h \neq 0 .\) Compute and simplify the difference quotient $$ \frac{f(x+h)-f(x)}{h} $$ $$f(x)=x-x^{2}$$

5 step solution

Problem 29

Could the following statement ever be the rule of a function? For input \(x,\) the output is the number whose square is \(x\) Why or why not? If there is a function with this rule, what is its domain and range?

5 step solution

Problem 30

List three different functions (other than the ones in Example 6 and Exercise 29 ), each of which is its own inverse. [Many correct answers are possible.]

3 step solution

Problem 30

Let \(f(x)=x^{2}+3 x,\) and let \(g(x)=f(x)+2\) (a) Write the rule of \(g(x)\) (b) Find the difference quotients of \(f(x)\) and \(g(x) .\) How are they related?

3 step solution

Problem 30

Verify that \((f \circ g)(x)=x\) and \((g \circ f)(x)=x\) for every \(x\) $$f(x)=\sqrt[3]{x-1}, \quad g(x)=x^{3}+1$$

4 step solution

Problem 30

Find the approximate location of all local maxima and minima of the function. $$l(x)=\frac{1}{1+x^{2}}$$

5 step solution

Problem 30

Assume \(h \neq 0 .\) Compute and simplify the difference quotient $$ \frac{f(x+h)-f(x)}{h} $$ $$f(x)=x^{3}$$

7 step solution

Problem 31

Let \(f(t)\) be the population of rabbits on Christy's property \(t\) years after she received 10 of them as a gift. $$\begin{array}{|c|c|}\hline t & f(t) \\\\\hline 0 & 10 \\\\\hline 1 & 23 \\\\\hline 2 & 48 \\\\\hline 3 & 64 \\\\\hline 4 & 70 \\\\\hline 5 & 71 \\\\\hline\end{array}$$ Compute the following, including units, or write "not enough information to tell." \(f^{-1}\) denotes the inverse function of \(f\). (a) \(f(2)\) (b) \(f^{-1}(48)\) (c) \(f^{-1}(71)\) (d) \(3 \cdot f^{-1}(70)\) (e) \(f^{-1}(2 \cdot 48)\) (f) \(f(70)\) (g) \(f^{-1}(4)\)

7 step solution

Problem 31

Let \(f(x)=x^{2}+5,\) and let \(g(x)=f(x-1)\) (a) Write the rule of \(g(x)\) and simplify. (b) Find the difference quotients of \(f(x)\) and \(g(x)\) (c) Let \(d(x)\) denote the difference quotient of \(f(x) .\) Show that the difference quotient of \(g(x)\) is \(d(x-1)\)

4 step solution

Problem 31

Verify that \((f \circ g)(x)=x\) and \((g \circ f)(x)=x\) for every \(x\) $$f(x)=\sqrt[3]{x}+2, \quad g(x)=(x-2)^{3}$$

4 step solution

Problem 31

Assume \(h \neq 0 .\) Compute and simplify the difference quotient $$ \frac{f(x+h)-f(x)}{h} $$ $$f(x)=\sqrt{x}$$

6 step solution

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