Chapter 10

College Algebra and Calculus: An Applied Approach · 279 exercises

Problem 15

In Exercises, use a graphing utility to graph the function. Be sure to choose an appropriate viewing window. $$ N(t)=500 e^{-0.2 t} $$

4 step solution

Problem 16

In Exercises, find the derivative of the function. $$ y=x^{2} e^{x}-2 x e^{x}+2 e^{x} $$

4 step solution

Problem 16

In Exercises, sketch the graph of the function. $$ y=5+\ln x $$

3 step solution

Problem 17

In Exercises, find the derivative of the function. $$ y=\ln \frac{x}{x+1} $$

3 step solution

Problem 17

In Exercises, sketch the graph of the function. $$ y=3 \ln x $$

3 step solution

Problem 17

In Exercises, determine an equation of the tangent line to the function at the given point. $$ y=e^{-2 x+x^{2}}, \quad(2,1) $$

3 step solution

Problem 17

In Exercises, use a graphing utility to graph the function. Be sure to choose an appropriate viewing window. $$ g(x)=\frac{2}{1+e^{x^{2}}} $$

3 step solution

Problem 18

Find the half-life of a radioactive material if after 1 year \(99.57 \%\) of the initial amount remains.

4 step solution

Problem 18

In Exercises, find the derivative of the function. $$ y=\ln \frac{x^{2}}{x^{2}+1} $$

4 step solution

Problem 18

In Exercises, sketch the graph of the function. $$ y=\frac{1}{4} \ln x $$

3 step solution

Problem 18

In Exercises, determine an equation of the tangent line to the function at the given point. $$ g(x)=e^{x^{3}}, \quad\left(-1, \frac{1}{e}\right) $$

3 step solution

Problem 18

In Exercises, use a graphing utility to graph the function. Be sure to choose an appropriate viewing window. $$ g(x)=\frac{10}{1+e^{-x}} $$

4 step solution

Problem 19

\({ }^{14} \mathrm{C}\) dating assumes that the carbon dioxide on the Earth today has the same radioactive content as it did centuries ago. If this is true, then the amount of \({ }^{14} \mathrm{C}\) absorbed by a tree that grew several centuries ago should be the same as the amount of \({ }^{14} \mathrm{C}\) absorbed by a similar tree today. A piece of ancient charcoal contains only \(15 \%\) as much of the radioactive carbon as a piece of modern charcoal. How long ago was the tree burned to make the ancient charcoal? (The half-life of \({ }^{14} \mathrm{C}\) is 5715 years.)

4 step solution

Problem 19

In Exercises, find the derivative of the function. $$ y=\ln \sqrt[3]{\frac{x-1}{x+1}} $$

7 step solution

Problem 19

In Exercises, determine an equation of the tangent line to the function at the given point. $$ y=x^{2} e^{-x}, \quad\left(2, \frac{4}{e^{2}}\right) $$

3 step solution

Problem 19

In Exercises, use a graphing utility to graph the function. Determine whether the function has any horizontal asymptotes and discuss the continuity of the function. $$ f(x)=\frac{e^{x}+e^{-x}}{2} $$

4 step solution

Problem 20

In Exercises, find the derivative of the function. $$ y=\ln \sqrt{\frac{x+1}{x-1}} $$

3 step solution

Problem 20

In Exercises, analytically show that the functions are inverse functions. Then use a graphing utility to show this graphically. $$ \begin{aligned} &f(x)=e^{x}-1 \\ &g(x)=\ln (x+1) \end{aligned} $$

3 step solution

Problem 20

In Exercises, determine an equation of the tangent line to the function at the given point. $$ y=\frac{x}{e^{2 x}}, \quad\left(1, \frac{1}{e^{2}}\right) $$

3 step solution

Problem 20

In Exercises, use a graphing utility to graph the function. Determine whether the function has any horizontal asymptotes and discuss the continuity of the function. $$ f(x)=\frac{e^{x}-e^{-x}}{2} $$

3 step solution

Problem 21

In Exercises, find the derivative of the function. $$ y=\ln \frac{\sqrt{4+x^{2}}}{x} $$

4 step solution

Problem 21

In Exercises, analytically show that the functions are inverse functions. Then use a graphing utility to show this graphically. $$ \begin{aligned} &f(x)=e^{2 x-1} \\ &g(x)=\frac{1}{2}+\ln \sqrt{x} \end{aligned} $$

2 step solution

Problem 21

In Exercises, determine an equation of the tangent line to the function at the given point. $$ y=\left(e^{2 x}+1\right)^{3}, \quad(0,8) $$

3 step solution

Problem 21

In Exercises, use a graphing utility to graph the function. Determine whether the function has any horizontal asymptotes and discuss the continuity of the function. $$ f(x)=\frac{2}{1+e^{1 / x}} $$

4 step solution

Problem 22

In Exercises, find exponential models \(y_{1}=C e^{k_{1} t}\) and \(y_{2}=C(2)^{k_{2} t}\) that pass through the points. Compare the values of \(k_{1}\) and \(k_{2} .\) Briefly explain your results. $$ (0,8),\left(20, \frac{1}{2}\right) $$

3 step solution

Problem 22

In Exercises, find the derivative of the function. $$ y=\ln \left(x \sqrt{4+x^{2}}\right) $$

5 step solution

Problem 22

In Exercises, determine an equation of the tangent line to the function at the given point. $$ y=\left(e^{4 x}-2\right)^{2}, \quad(0,1) $$

3 step solution

Problem 22

In Exercises, use a graphing utility to graph the function. Determine whether the function has any horizontal asymptotes and discuss the continuity of the function. $$ f(x)=\frac{2}{1+2 e^{-0.2 x}} $$

3 step solution

Problem 23

The number of a certain type of bacteria increases continuously at a rate proportional to the number present. There are 150 present at a given time and 450 present 5 hours later. (a) How many will there be 10 hours after the initial time? (b) How long will it take for the population to double? (c) Does the answer to part (b) depend on the starting time? Explain your reasoning.

4 step solution

Problem 23

In Exercises, find the derivative of the function. $$ g(x)=e^{-x} \ln x $$

3 step solution

Problem 23

In Exercises, apply the inverse properties of logarithmic and exponential functions to simplify the expression. $$ \ln e^{x^{2}} $$

2 step solution

Problem 23

In Exercises, find \(d y / d x\) implicitly. $$ x e^{y}-10 x+3 y=0 $$

3 step solution

Problem 23

In Exercises, use a graphing utility to graph the function. $$ y=2^{x-1} $$

5 step solution

Problem 24

In Exercises, find the derivative of the function. $$ f(x)=x \ln e^{x^{2}} $$

3 step solution

Problem 24

In Exercises, apply the inverse properties of logarithmic and exponential functions to simplify the expression. $$ \ln e^{2 x-1} $$

2 step solution

Problem 24

In Exercises, find \(d y / d x\) implicitly. $$ x^{2} y-e^{y}-4=0 $$

4 step solution

Problem 24

Use a graphing utility to graph the function. Describe the shape of the graph for very large and very small values of \(x\). (a) \(f(x)=\frac{8}{1+e^{-0.5 x}}\) (b) \(g(x)=\frac{8}{1+e^{-0.5 / x}}\)

4 step solution

Problem 24

In Exercises, use a graphing utility to graph the function. $$ y=4^{x}+3 $$

3 step solution

Problem 25

In Exercises, find the derivative of the function. $$ g(x)=\ln \frac{e^{x}+e^{-x}}{2} $$

4 step solution

Problem 25

In Exercises, apply the inverse properties of logarithmic and exponential functions to simplify the expression. $$ e^{\ln (5 x+2)} $$

2 step solution

Problem 25

In Exercises, find \(d y / d x\) implicitly. $$ x^{2} e^{-x}+2 y^{2}-x y=0 $$

4 step solution

Problem 25

In Exercises, use a graphing utility to graph the function. $$ y=-2^{x} $$

3 step solution

Problem 26

In Exercises, find the derivative of the function. $$ f(x)=\ln \frac{1+e^{x}}{1-e^{x}} $$

5 step solution

Problem 26

In Exercises, apply the inverse properties of logarithmic and exponential functions to simplify the expression. $$ e^{\ln \sqrt{x}} $$

3 step solution

Problem 26

In Exercises, find \(d y / d x\) implicitly. $$ e^{x y}+x^{2}-y^{2}=10 $$

3 step solution

Problem 26

In Exercises, use a graphing utility to graph the function. $$ y=-5^{x} $$

3 step solution

Problem 27

In Exercises, apply the inverse properties of logarithmic and exponential functions to simplify the expression. $$ -1+\ln e^{2 x} $$

3 step solution

Problem 27

In Exercises, find the second derivative. $$ f(x)=2 e^{3 x}+3 e^{-2 x} $$

2 step solution

Problem 27

In Exercises, use a graphing utility to graph the function. $$ y=3^{-x^{2}} $$

5 step solution

Problem 28

In Exercises, apply the inverse properties of logarithmic and exponential functions to simplify the expression. $$ -8+e^{\ln x^{3}} $$

3 step solution

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