Chapter 4

Precalculus : Building Concepts and Connections · 431 exercises

Problem 48

In Exercises \(47-52,\) let \(b=\log\) k. Write each expression in terms of b. Assume \(k>0\). $$\log 100 k$$

3 step solution

Problem 49

Use the change-of-base formula to evaluate each logarithm using a calculator. Round answers to four decimal places. $$. \log _{7} 150$$

3 step solution

Problem 49

Explain why the function \(f(t)=e^{(1 / 2) t}\) cannot model exponential decay.

5 step solution

Problem 49

Find the inverse of the given function. Then graph the given function and its inverse on the same set of axes. $$f(x)=-4 x^{5}+9$$

4 step solution

Problem 49

Solve the logarithmic equation and eliminate any extraneous solutions. If there are no solutions, so state. $$\ln (2 x)=1+\ln (x+3)$$

5 step solution

Problem 49

In Exercises \(47-52,\) let \(b=\log\) k. Write each expression in terms of b. Assume \(k>0\). $$\log k^{3}$$

2 step solution

Problem 50

Find the inverse of the given function. Then graph the given function and its inverse on the same set of axes. $$g(x)=2 x^{5}-6$$

2 step solution

Problem 50

Solve the logarithmic equation and eliminate any extraneous solutions. If there are no solutions, so state. $$\log _{3} x=2+\log _{3}(x-2)$$

5 step solution

Problem 50

In Exercises \(47-52,\) let \(b=\log\) k. Write each expression in terms of b. Assume \(k>0\). $$\log k^{4}$$

2 step solution

Problem 50

Use the change-of-base formula to evaluate each logarithm using a calculator. Round answers to four decimal places. $$\log _{7} 230$$

3 step solution

Problem 51

Find the inverse of the given function. Then graph the given function and its inverse on the same set of axes. $$f(x)=\frac{1}{x}$$

3 step solution

Problem 51

Solve the logarithmic equation and eliminate any extraneous solutions. If there are no solutions, so state. $$\log (3 x+1)-\log \left(x^{2}+1\right)=0$$

4 step solution

Problem 51

In Exercises \(47-52,\) let \(b=\log\) k. Write each expression in terms of b. Assume \(k>0\). $$\log \frac{1}{k}$$

4 step solution

Problem 51

Use the definition of a logarithm to solve for \(x\). $$\log _{2} x=3$$

3 step solution

Problem 52

Find the inverse of the given function. Then graph the given function and its inverse on the same set of axes. $$g(x)=\frac{-1}{2 x}$$

3 step solution

Problem 52

Solve the logarithmic equation and eliminate any extraneous solutions. If there are no solutions, so state. $$\log (x+5)-\log \left(4 x^{2}+5\right)=0$$

3 step solution

Problem 52

In Exercises \(47-52,\) let \(b=\log\) k. Write each expression in terms of b. Assume \(k>0\). $$\log \frac{1}{k^{3}}$$

3 step solution

Problem 52

Use the definition of a logarithm to solve for \(x\). $$ \log _{5} \sqrt{5}=x$$

3 step solution

Problem 53

Find the inverse of the given function. Then graph the given function and its inverse on the same set of axes. $$g(x)=(x-1)^{2}, x \geq 1$$

3 step solution

Problem 53

Solve the logarithmic equation and eliminate any extraneous solutions. If there are no solutions, so state. $$\log (2 x+5)+\log (x+1)=1$$

4 step solution

Problem 53

In Exercises \(53-64,\) simplify each expression. Assume that each variable expression is defined for appropriate values of \(x .\) Do not use a calculator. $$\log 10^{\sqrt{2}}$$

2 step solution

Problem 53

Use a graphing utility to solve each equation for \(x.\) $$5=3^{x}$$

3 step solution

Problem 53

Use the definition of a logarithm to solve for \(x\). $$\log _{3} x=\frac{1}{3}$$

2 step solution

Problem 54

Find the inverse of the given function. Then graph the given function and its inverse on the same set of axes. $$g(x)=(x+2)^{2}, x \geq-2$$

4 step solution

Problem 54

Solve the logarithmic equation and eliminate any extraneous solutions. If there are no solutions, so state. $$\log (3 x+1)+\log (x+1)=1$$

4 step solution

Problem 54

In Exercises \(53-64,\) simplify each expression. Assume that each variable expression is defined for appropriate values of \(x .\) Do not use a calculator. $$\log 10^{2 x}$$

3 step solution

Problem 54

Use a graphing utility to solve each equation for \(x.\) $$7=4^{x}$$

3 step solution

Problem 54

Use the definition of a logarithm to solve for \(x\). $$\log _{6} x=-2$$

4 step solution

Problem 55

Find the inverse of the given function. Then graph the given function and its inverse on the same set of axes. $$f(x)=\sqrt{x+3}, x \geq-3$$

3 step solution

Problem 55

Solve the logarithmic equation and eliminate any extraneous solutions. If there are no solutions, so state. $$\log _{2}(x+5)=\log _{2}(x)+\log _{2}(x-3)$$

6 step solution

Problem 55

In Exercises \(53-64,\) simplify each expression. Assume that each variable expression is defined for appropriate values of \(x .\) Do not use a calculator. $$\ln e^{\sqrt{3}}$$

2 step solution

Problem 55

Use a graphing utility to solve each equation for \(x.\) $$10=2^{-x}$$

3 step solution

Problem 56

Find the inverse of the given function. Then graph the given function and its inverse on the same set of axes. $$f(x)=\sqrt{x-4}, x \geq 4$$

2 step solution

Problem 56

Solve the logarithmic equation and eliminate any extraneous solutions. If there are no solutions, so state. $$\ln 2 x-\ln \left(x^{2}+1\right)=\ln 1$$

4 step solution

Problem 56

In Exercises \(53-64,\) simplify each expression. Assume that each variable expression is defined for appropriate values of \(x .\) Do not use a calculator. $$\ln e^{(x+1)}$$

2 step solution

Problem 56

Use a graphing utility to solve each equation for \(x.\) $$20=100(5)^{-x}$$

3 step solution

Problem 56

Use the definition of a logarithm to solve for \(x\). $$\log _{x} 9=\frac{1}{2}$$

4 step solution

Problem 57

Find the inverse of the given function. Then graph the given function and its inverse on the same set of axes. $$f(x)=\frac{2 x}{x-1}$$

2 step solution

Problem 57

Solve the logarithmic equation and eliminate any extraneous solutions. If there are no solutions, so state. $$2 \ln x+\ln (x-1)=3.1$$

5 step solution

Problem 57

In Exercises \(53-64,\) simplify each expression. Assume that each variable expression is defined for appropriate values of \(x .\) Do not use a calculator. $$10^{\log (5 x)}$$

4 step solution

Problem 57

Use a graphing utility to solve each equation for \(x.\) $$100=50 e^{0.06 x}$$

4 step solution

Problem 57

Find the domain of each function. Use your answer to help you graph the function, and label all asymptotes. $$f(x)=2 \log x$$

3 step solution

Problem 58

Find the inverse of the given function. Then graph the given function and its inverse on the same set of axes. $$f(x)=\frac{x+3}{x}$$

4 step solution

Problem 58

Solve the logarithmic equation and eliminate any extraneous solutions. If there are no solutions, so state. $$-\ln x-\ln (x+2)=2.5$$

4 step solution

Problem 58

In Exercises \(53-64,\) simplify each expression. Assume that each variable expression is defined for appropriate values of \(x .\) Do not use a calculator. $$e^{\ln \left(5 x^{2}-1\right)}$$

2 step solution

Problem 58

Use a graphing utility to solve each equation for \(x.\) $$25=50 e^{-0.05 x}$$

3 step solution

Problem 58

Find the domain of each function. Use your answer to help you graph the function, and label all asymptotes. $$f(x)=4 \ln x$$

3 step solution

Problem 59

Solve the logarithmic equation and eliminate any extraneous solutions. If there are no solutions, so state. $$\log |x-2|+\log |x|=1.2$$

5 step solution

Problem 59

In Exercises \(53-64,\) simplify each expression. Assume that each variable expression is defined for appropriate values of \(x .\) Do not use a calculator. $$10^{\log (3 x+1)}$$

2 step solution

Problem 59

Consider the function \(f(x)=x e^{-x}.\) (a) Use a graphing utility to graph this function, with \(x\) ranging from -5 to \(5 .\) You may need to scroll through the table of values to set an appropriate scale for the vertical axis. (b) What are the domain and range of \(f ?\) (c) What are the \(x\) - and \(y\) -intercepts, if any, of the graph of this function? (d) Describe the behavior of the function as \(x\) approaches \(\pm \infty.\)

4 step solution

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