Chapter 10

Algebra for College Students · 388 exercises

Problem 59

Explain how to determine \(\log _{4} 76\) without using Property 10.9.

5 step solution

Problem 59

Perform the following calculations and express answers to the nearest hundredth. $$ \frac{\ln 2}{0.03} $$

4 step solution

Problem 59

Given that \(\log _{2} 5=2.3219\) and \(\log _{2} 7=2.8074\), evaluate each expression by using Properties \(10.5-10.7\) \(\log _{2} 80\)

4 step solution

Problem 59

Find the intervals on which the given function is increasing and the intervals on which it is decreasing. $$ f(x)=x^{2}+1 $$

5 step solution

Problem 59

Graph \(f(x)=e^{x}\). Where should the graphs of \(f(x)=\) \(e^{x-4}, f(x)=e^{x-6}\), and \(f(x)=e^{x+5}\) be located? Graph all three functions on the same set of axes with \(f(x)=e^{x}\).

5 step solution

Problem 60

Perform the following calculations and express answers to the nearest hundredth. $$ \frac{\log 2}{5 \log 1.02} $$

5 step solution

Problem 60

Given that \(\log _{8} 5=0.7740\) and \(\log _{8} 11=1.1531\), evaluate each expression using Properties \(10.5-10.7\) \(\log _{8} 55\)

4 step solution

Problem 60

Find the intervals on which the given function is increasing and the intervals on which it is decreasing. $$ f(x)=x^{3} $$

5 step solution

Problem 60

Graph \(f(x)=e^{x}\). Now predict the graphs for \(f(x)=\) \(-e^{x}, f(x)=e^{-x}\), and \(f(x)=-e^{-x}\). Graph all three functions on the same set of axes with \(f(x)=e^{x}\).

5 step solution

Problem 61

Explain how you would solve the equation \(2^{x}=64\) and also how you would solve the equation \(2^{x}=53\).

7 step solution

Problem 61

Perform the following calculations and express answers to the nearest hundredth. $$ \frac{\log 5}{3 \log 1.07} $$

5 step solution

Problem 61

Given that \(\log _{8} 5=0.7740\) and \(\log _{8} 11=1.1531\), evaluate each expression using Properties \(10.5-10.7\) \(\log _{8}\left(\frac{5}{11}\right)\)

4 step solution

Problem 61

Find the intervals on which the given function is increasing and the intervals on which it is decreasing. $$ f(x)=-3 x+1 $$

5 step solution

Problem 61

How do you think the graphs of \(f(x)=e^{x}, f(x)=e^{2 x}\), and \(f(x)=2 e^{x}\) will compare? Graph them on the same set of axes to see if you were correct.

4 step solution

Problem 62

How do logarithms with a base of 9 compare to logarithms with a base of 3 ? Explain how you reached this conclusion.

4 step solution

Problem 62

Given that \(\log _{8} 5=0.7740\) and \(\log _{8} 11=1.1531\), evaluate each expression using Properties \(10.5-10.7\) \(\log _{8} 25\)

4 step solution

Problem 62

Find the intervals on which the given function is increasing and the intervals on which it is decreasing. $$ f(x)=(x-3)^{2}+1 $$

5 step solution

Problem 62

Find an approximate solution, to the nearest hundredth, for each of the following equations by graphing the appropriate function and finding the \(x\) intercept. (a) \(e^{x}=7\) (b) \(e^{x}=21\) (c) \(e^{x}=53\) (d) \(2 e^{x}=60\) (e) \(e^{x+1}=150\) (f) \(e^{x-2}=300\)

5 step solution

Problem 63

Given that \(\log _{8} 5=0.7740\) and \(\log _{8} 11=1.1531\), evaluate each expression using Properties \(10.5-10.7\) \(\log _{8} \sqrt{11}\)

5 step solution

Problem 63

Find the intervals on which the given function is increasing and the intervals on which it is decreasing. $$ f(x)=-(x+2)^{2}-1 $$

4 step solution

Problem 64

Graph \(f(x)=x, f(x)=e^{x}\), and \(f(x)=\ln x\) on the same set of axes.

6 step solution

Problem 64

Given that \(\log _{8} 5=0.7740\) and \(\log _{8} 11=1.1531\), evaluate each expression using Properties \(10.5-10.7\) \(\log _{8}(5)^{2 / 3}\)

4 step solution

Problem 64

Find the intervals on which the given function is increasing and the intervals on which it is decreasing. $$ f(x)=x^{2}-2 x+6 $$

4 step solution

Problem 64

How long will it take \(\$ 500\) to be worth \(\$ 1500\) if it is invested at \(7.5 \%\) interest compounded semiannually?

8 step solution

Problem 65

Solve the equation \(\frac{5^{x}-5^{-x}}{2}=3\). Express your answer to the nearest hundredth. \(\\{1.13\\}\)

12 step solution

Problem 65

Graph \(f(x)=x, f(x)=10^{x}\), and \(f(x)=\log x\) on the same set of axes.

5 step solution

Problem 65

Given that \(\log _{8} 5=0.7740\) and \(\log _{8} 11=1.1531\), evaluate each expression using Properties \(10.5-10.7\) \(\log _{8} 88\)

5 step solution

Problem 65

Find the intervals on which the given function is increasing and the intervals on which it is decreasing. $$ f(x)=-2 x^{2}-16 x-35 $$

4 step solution

Problem 65

How long will it take \(\$ 5000\) to triple if it is invested at \(6.75 \%\) interest compounded quarterly?

5 step solution

Problem 66

$$ \text { Solve the equation } y=\frac{10^{x}+10^{-x}}{2} \text { for } x \text { in terms of } y \text {. } $$

4 step solution

Problem 66

Graph \(f(x)=\ln x\). How should the graphs of \(f(x)=2\) \(\ln x, f(x)=4 \ln x\), and \(f(x)=6 \ln x\) compare to the graph of \(f(x)=\ln x\) ? Graph the three functions on the same set of axes with \(f(x)=\ln x\).

5 step solution

Problem 66

Given that \(\log _{8} 5=0.7740\) and \(\log _{8} 11=1.1531\), evaluate each expression using Properties \(10.5-10.7\) \(\log _{8} 320\)

5 step solution

Problem 66

Find the intervals on which the given function is increasing and the intervals on which it is decreasing. $$ f(x)=x^{2}+3 x-1 $$

4 step solution

Problem 67

$$ \text { Solve the equation } y=\frac{e^{x}-e^{-x}}{2} \text { for } x \text { in terms of } y \text {. } $$

4 step solution

Problem 67

Graph \(f(x)=\log x\). Now predict the graphs for \(f(x)=\) \(2+\log x, f(x)=-2+\log x\), and \(f(x)=-6+\log x\). Graph the three functions on the same set of axes with \(f(x)=\log x\).

5 step solution

Problem 67

Given that \(\log _{8} 5=0.7740\) and \(\log _{8} 11=1.1531\), evaluate each expression using Properties \(10.5-10.7\) \(\log _{8}\left(\frac{25}{11}\right)\)

3 step solution

Problem 67

Does the function \(f(x)=4\) have an inverse? Explain your answer.

4 step solution

Problem 68

Graph \(\ln x\). Now predict the graphs for \(f(x)=\ln (x-2)\), \(f(x)=\ln (x-6)\), and \(f(x)=\ln (x+4)\). Graph the three functions on the same set of axes with \(f(x)=\ln x\).

5 step solution

Problem 68

Given that \(\log _{8} 5=0.7740\) and \(\log _{8} 11=1.1531\), evaluate each expression using Properties \(10.5-10.7\) \(\log _{8}\left(\frac{121}{25}\right)\)

6 step solution

Problem 69

Graph \(f(x)=x, f(x)=2^{x}\), and \(f(x)=\log _{2} x\) on the same set of axes.

6 step solution

Problem 69

For each of the following, (a) predict the general shape and location of the graph, and (b) use your graphing calculator to graph the function to check your prediction. (a) \(f(x)=\log x+\ln x\) (b) \(f(x)=\log x-\ln x\) (c) \(f(x)=\ln x-\log x\) (d) \(f(x)=\ln x^{2}\)

9 step solution

Problem 69

Express each of the following as the sum or difference of simpler logarithmic quantities. Assume that all variables represent positive real numbers. For example, $$ \begin{aligned} \log _{b} \frac{x^{3}}{y^{2}} &=\log _{b} x^{3}-\log _{b} y^{2} \\ &=3 \log _{b} x-2 \log _{b} y \end{aligned} $$ $$ \log _{b} x y z $$

4 step solution

Problem 69

Are the functions \(f(x)=x^{4}\) and \(g(x)=\sqrt[4]{x}\) inverses of each other? Explain your answer.

4 step solution

Problem 70

Graph \(f(x)=x, f(x)=(0.5)^{x}\), and \(f(x)=\log _{0.5} x\) on the same set of axes.

6 step solution

Problem 70

Express each of the following as the sum or difference of simpler logarithmic quantities. Assume that all variables represent positive real numbers. For example, $$ \begin{aligned} \log _{b} \frac{x^{3}}{y^{2}} &=\log _{b} x^{3}-\log _{b} y^{2} \\ &=3 \log _{b} x-2 \log _{b} y \end{aligned} $$ $$ \log _{h} 5 x $$

4 step solution

Problem 71

Graph \(f(x)=\log _{2} x\). Now predict the graphs for \(f(x)=\) \(\log _{3} x, f(x)=\log _{4} x\), and \(f(x)=\log _{8} x\). Graph these three functions on the same set of axes with $$ f(x)=\log _{2} x \text {. } $$

5 step solution

Problem 71

Express each of the following as the sum or difference of simpler logarithmic quantities. Assume that all variables represent positive real numbers. For example, $$ \begin{aligned} \log _{b} \frac{x^{3}}{y^{2}} &=\log _{b} x^{3}-\log _{b} y^{2} \\ &=3 \log _{b} x-2 \log _{b} y \end{aligned} $$ $$ \log _{b}\left(\frac{y}{z}\right) $$

2 step solution

Problem 71

The function notation and the operation of composition can be used to find inverses as follows: To find the inverse of \(f(x)=5 x+3\), we know that \(f\left(f^{-1}(x)\right)\) must produce \(x\). Therefore $$ \begin{aligned} f\left(f^{-1}(x)\right)=5\left[f^{-1}(x)\right]+3 &=x \\ 5\left[f^{-1}(x)\right] &=x-3 \\ f^{-1}(x) &=\frac{x-3}{5} \end{aligned} $$

4 step solution

Problem 72

Graph \(f(x)=\log _{5} x\). Now predict the graphs for \(f(x)=\) \(2 \log _{5} x, f(x)=-4 \log _{5} x\), and \(f(x)=\log _{5}(x+4)\). Graph these three functions on the same set of axes with \(f(x)=\log _{5} x\).

6 step solution

Problem 72

Express each of the following as the sum or difference of simpler logarithmic quantities. Assume that all variables represent positive real numbers. For example, $$ \begin{aligned} \log _{b} \frac{x^{3}}{y^{2}} &=\log _{b} x^{3}-\log _{b} y^{2} \\ &=3 \log _{b} x-2 \log _{b} y \end{aligned} $$ $$ \log _{b}\left(\frac{x^{2}}{y}\right) $$

3 step solution

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