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