Chapter 8

College Algebra and Calculus: An Applied Approach · 242 exercises

Problem 20

In Exercises, find the absolute extrema of the function on the closed interval. Use a graphing utility to verify your results. $$ f(x)=\frac{1}{3}(2 x+5), \quad[0,5] $$

4 step solution

Problem 20

In Exercises, find the critical numbers and the open intervals on which the function is increasing or decreasing. Then use a graphing utility to graph the function. $$ y=x^{2 / 3}-4 $$

4 step solution

Problem 20

In Exercises, find the third derivative of the function. $$ f(x)=\left(x^{3}-6\right)^{4} $$

3 step solution

Problem 21

In Exercises, find all relative extrema of the function. Use the Second- Derivative Test when applicable. $$ f(x)=\frac{x}{x-1} $$

3 step solution

Problem 21

In Exercises, find the absolute extrema of the function on the closed interval. Use a graphing utility to verify your results. $$ f(x)=5-2 x^{2}, \quad[0,3] $$

4 step solution

Problem 21

In Exercises, find the critical numbers and the open intervals on which the function is increasing or decreasing. Then use a graphing utility to graph the function. $$ g(x)=(x-1)^{1 / 3} $$

4 step solution

Problem 21

A (square) baseball diamond has sides that are 90 feet long (see figure). A player 26 feet from third base is running at a speed of 30 feet per second. At what rate is the player's distance from home plate changing?

5 step solution

Problem 21

In Exercises, find the third derivative of the function. $$ f(x)=\frac{3}{16 x^{2}} $$

3 step solution

Problem 22

In Exercises, find all relative extrema of the function. Use the Second- Derivative Test when applicable. $$ f(x)=\frac{x}{x^{2}-1} $$

4 step solution

Problem 22

In Exercises, find the absolute extrema of the function on the closed interval. Use a graphing utility to verify your results. $$ f(x)=x^{2}+2 x-4, \quad[-1,1] $$

4 step solution

Problem 22

In Exercises, find the critical numbers and the open intervals on which the function is increasing or decreasing. Then use a graphing utility to graph the function. $$ g(x)=(x-1)^{2 / 3} $$

3 step solution

Problem 22

A retail sporting goods store estimates that weekly sales \(S\) and weekly advertising costs \(x\) are related by the equation \(S=2250+50 x+0.35 x^{2}\). The current weekly advertising costs are \(\$ 1500\), and these costs are increasing at a rate of \(\$ 125\) per week. Find the current rate of change of weekly sales.

3 step solution

Problem 22

In Exercises, find the third derivative of the function. $$ f(x)=\frac{1}{x} $$

3 step solution

Problem 23

In Exercise, use a graphing utility to estimate graphically all relative extrema of the function. $$ f(x)=\frac{1}{2} x^{4}-\frac{1}{3} x^{3}-\frac{1}{2} x^{2} $$

3 step solution

Problem 23

In Exercises, find the absolute extrema of the function on the closed interval. Use a graphing utility to verify your results. $$ f(x)=x^{3}-3 x^{2}, \quad[-1,3] $$

4 step solution

Problem 23

In Exercises, find the critical numbers and the open intervals on which the function is increasing or decreasing. Then use a graphing utility to graph the function. $$ f(x)=-2 x^{2}+4 x+3 $$

4 step solution

Problem 23

An accident at an oil drilling platform is causing a circular oil slick. The slick is \(0.08\) foot thick, and when the radius of the slick is 150 feet, the radius is increasing at the rate of \(0.5\) foot per minute. At what rate (in cubic feet per minute) is oil flowing from the site of the accident?

3 step solution

Problem 24

In Exercise, use a graphing utility to estimate graphically all relative extrema of the function. $$ f(x)=-\frac{1}{3} x^{5}-\frac{1}{2} x^{4}+x $$

4 step solution

Problem 24

In Exercises, find the absolute extrema of the function on the closed interval. Use a graphing utility to verify your results. $$ f(x)=x^{3}-12 x, \quad[0,4] $$

4 step solution

Problem 24

In Exercises, find the critical numbers and the open intervals on which the function is increasing or decreasing. Then use a graphing utility to graph the function. $$ f(x)=x^{2}+8 x+10 $$

5 step solution

Problem 24

A company is increasing the production of a product at the rate of 25 units per week. The demand and cost functions for the product are given by \(p=50-0.01 x\) and \(C=4000+40 x-0.02 x^{2} .\) Find the rate of change of the profit with respect to time when the weekly sales are \(x=800\) units. Use a graphing utility to graph the profit function, and use the zoom and trace features of the graphing utility to verify your result.

4 step solution

Problem 24

In Exercises, find the given value. $$ f(x)=9-x^{2} \quad f^{\prime \prime}(-\sqrt{5}) $$

3 step solution

Problem 25

In Exercise, use a graphing utility to estimate graphically all relative extrema of the function. $$ f(x)=5+3 x^{2}-x^{3} $$

3 step solution

Problem 25

In Exercises, find the absolute extrema of the function on the closed interval. Use a graphing utility to verify your results. $$ h(s)=\frac{1}{3-s}, \quad[0,2] $$

3 step solution

Problem 25

In Exercises, find the critical numbers and the open intervals on which the function is increasing or decreasing. Then use a graphing utility to graph the function. $$ y=3 x^{3}+12 x^{2}+15 x $$

4 step solution

Problem 25

The profit for a product is increasing at a rate of \(\$ 5600\) per week. The demand and cost functions for the product are given by \(p=6000-25 x\) and \(C=2400 x\) + 5200 . Find the rate of change of sales with respect to time when the weekly sales are \(x=44\) units.

5 step solution

Problem 26

In Exercise, use a graphing utility to estimate graphically all relative extrema of the function. $$ f(x)=3 x^{3}+5 x^{2}-2 $$

3 step solution

Problem 26

In Exercises, find the absolute extrema of the function on the closed interval. Use a graphing utility to verify your results. $$ h(t)=\frac{t}{t-2}, \quad[3,5] $$

4 step solution

Problem 26

In Exercises, find the critical numbers and the open intervals on which the function is increasing or decreasing. Then use a graphing utility to graph the function. $$ y=x^{3}-3 x+2 $$

4 step solution

Problem 26

The annual cost (in millions of dollars) for a government agency to seize \(p \%\) of an illegal drug is given by \(C=\frac{528 p}{100-p}, 0 \leq p<100\) The agency's goal is to increase \(p\) by \(5 \%\) per year. Find the rates of change of the cost when (a) \(p=30 \%\) and (b) \(p=60 \%\). Use a graphing utility to graph \(C\). What happens to the graph of \(C\) as \(p\) approaches \(100 ?\)

3 step solution

Problem 27

In Exercises, find the absolute extrema of the function on the closed interval. Use a graphing utility to verify your results. $$ f(x)=3 x^{2 / 3}-2 x, \quad[-1,2] $$

4 step solution

Problem 27

In Exercises, find the critical numbers and the open intervals on which the function is increasing or decreasing. Then use a graphing utility to graph the function. $$ f(x)=x \sqrt{x+1} $$

3 step solution

Problem 28

In Exercises, find the absolute extrema of the function on the closed interval. Use a graphing utility to verify your results. $$ g(t)=\frac{t^{2}}{t^{2}+3}, \quad[-1,1] $$

4 step solution

Problem 28

In Exercises, find the critical numbers and the open intervals on which the function is increasing or decreasing. Then use a graphing utility to graph the function. $$ h(x)=x \sqrt[3]{x-1} $$

3 step solution

Problem 29

In Exercises, find the absolute extrema of the function on the closed interval. Use a graphing utility to verify your results. $$ h(t)=(t-1)^{2 / 3}, \quad[-7,2] $$

5 step solution

Problem 29

In Exercises, find the critical numbers and the open intervals on which the function is increasing or decreasing. Then use a graphing utility to graph the function. $$ f(x)=x^{4}-2 x^{3} $$

4 step solution

Problem 29

In Exercises, find the higher-order derivative. $$ f^{\prime}(x)=2 x^{2} $$

3 step solution

Problem 30

In Exercises, find the absolute extrema of the function on the closed interval. Use a graphing utility to verify your results. $$ g(x)=4\left(1+\frac{1}{x}+\frac{1}{x^{2}}\right), \quad[-4,5] $$

3 step solution

Problem 30

In Exercises, find the critical numbers and the open intervals on which the function is increasing or decreasing. Then use a graphing utility to graph the function. $$ f(x)=\frac{1}{i} x^{4}-2 x^{2} $$

4 step solution

Problem 30

In Exercises, find the higher-order derivative. $$ f^{\prime \prime}(x)=20 x^{3}-36 x^{2} $$

3 step solution

Problem 31

In Exercises, find the point(s) of inflection of the graph of the function. $$ f(x)=x^{3}-9 x^{2}+24 x-18 $$

5 step solution

Problem 31

In Exercises, find the critical numbers and the open intervals on which the function is increasing or decreasing. Then use a graphing utility to graph the function. $$ f(x)=\frac{x}{x^{2}+4} $$

4 step solution

Problem 31

In Exercises, find the higher-order derivative. $$ f^{\prime \prime \prime}(x)=(3 x-1) / x $$

3 step solution

Problem 32

In Exercises, find the point(s) of inflection of the graph of the function. $$ f(x)=x(6-x)^{2} $$

5 step solution

Problem 32

In Exercises, find the critical numbers and the open intervals on which the function is increasing or decreasing. Then use a graphing utility to graph the function. $$ f(x)=\frac{x^{2}}{x^{2}+4} $$

4 step solution

Problem 33

In Exercises, find the point(s) of inflection of the graph of the function. $$ f(x)=(x-1)^{3}(x-5) $$

4 step solution

Problem 33

In Exercises, use a graphing utility to find graphically the absolute extrema of the function on the closed interval. $$ f(x)=0.4 x^{3}-1.8 x^{2}+x-3, \quad[0,5] $$

4 step solution

Problem 33

In Exercises, find the critical numbers and the open intervals on which the function is increasing or decreasing. (Hint: Check for discontinuities.) Sketch the graph of the function. $$ f(x)=\frac{2 x}{16-x^{2}} $$

4 step solution

Problem 34

In Exercises, find the point(s) of inflection of the graph of the function. $$ f(x)=x^{4}-18 x^{2}+5 $$

5 step solution

Problem 34

In Exercises, use a graphing utility to find graphically the absolute extrema of the function on the closed interval. $$ f(x)=3.2 x^{5}+5 x^{3}-3.5 x, \quad[0,1] $$

3 step solution

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