Chapter 5

Calculus A New Horizon · 139 exercises

Problem 21

Find: (a) the intervals on which \(f\) is increasing, (b) the intervals on which \(f\) is decreasing, (c) the open intervals on which \(f\) is concave up. (d) the open intervals on which \(f\) is concave down, and (e) the \(x\) -coordinates of all inflection points. $$f(x)=e^{-x^{2} / 2}$$

6 step solution

Problem 21

Use any method to find the relative extrema of the function \(f\). $$f(x)=x^{3}+5 x-2$$

4 step solution

Problem 22

Find: (a) the intervals on which \(f\) is increasing, (b) the intervals on which \(f\) is decreasing, (c) the open intervals on which \(f\) is concave up. (d) the open intervals on which \(f\) is concave down, and (e) the \(x\) -coordinates of all inflection points. $$f(x)=x e^{x^{2}}$$

5 step solution

Problem 22

The graph of the rational function crosses a horizontal asymptote. Give a complete graph of the function, and label the coordinates of the stationary points and inflection points. Show the horizontal and vertical asymptotes, and label the point(s) where the graph crosses a horizontal asymptote. Check your work with a graphing utility. $$2+\frac{3}{x}-\frac{1}{x^{3}}$$

6 step solution

Problem 22

Use any method to find the relative extrema of the function \(f\). $$f(x)=x^{4}-2 x^{2}+7$$

3 step solution

Problem 23

Find: (a) the intervals on which \(f\) is increasing, (b) the intervals on which \(f\) is decreasing, (c) the open intervals on which \(f\) is concave up. (d) the open intervals on which \(f\) is concave down, and (e) the \(x\) -coordinates of all inflection points. $$f(x)=\ln \left(1+x^{2}\right)$$

6 step solution

Problem 23

Use any method to find the relative extrema of the function \(f\). $$f(x)=x(x-1)^{2}$$

5 step solution

Problem 24

Find: (a) the intervals on which \(f\) is increasing, (b) the intervals on which \(f\) is decreasing, (c) the open intervals on which \(f\) is concave up. (d) the open intervals on which \(f\) is concave down, and (e) the \(x\) -coordinates of all inflection points. $$f(x)=x^{2} \ln x$$

6 step solution

Problem 24

Sketch the general shape of the graph of \(y=x^{1 / n},\) and then explain in words what happens to the shape of the graph as \(n\) increases if (a) \(n\) is a positive even integer (b) \(n\) is a positive odd integer.

5 step solution

Problem 24

Use any method to find the relative extrema of the function \(f\). $$f(x)=x^{4}+2 x^{3}$$

4 step solution

Problem 25

Analyze the trigonometric function \(f\) over the specified interval, stating where \(f\) is increasing. decreasing, concave up, and concave down, and stating the \(x\) coordinates of all inflection points. Confirm that your results are consistent with the graph of \(f\) generated with a graphing utility. $$f(x)=\cos x ;[0,2 \pi]$$

6 step solution

Problem 25

Use any method to find the relative extrema of the function \(f\). $$f(x)=2 x^{2}-x^{4}$$

4 step solution

Problem 26

Analyze the trigonometric function \(f\) over the specified interval, stating where \(f\) is increasing. decreasing, concave up, and concave down, and stating the \(x\) coordinates of all inflection points. Confirm that your results are consistent with the graph of \(f\) generated with a graphing utility. $$f(x)=\sin ^{2} 2 x ;[0, \pi]$$

6 step solution

Problem 26

Use any method to find the relative extrema of the function \(f\). $$f(x)=(2 x-1)^{5}$$

4 step solution

Problem 27

Analyze the trigonometric function \(f\) over the specified interval, stating where \(f\) is increasing. decreasing, concave up, and concave down, and stating the \(x\) coordinates of all inflection points. Confirm that your results are consistent with the graph of \(f\) generated with a graphing utility. $$f(x)=\tan x ;(-\pi / 2, \pi / 2)$$

6 step solution

Problem 27

Give a complete graph of the function, and identify the location of all critical points and inflection poir s. Check your work with a graphing utility. $$2 x+3 x^{2 / 3}$$

7 step solution

Problem 27

Use any method to find the relative extrema of the function \(f\). $$f(x)=x^{4 / 5}$$

4 step solution

Problem 28

Analyze the trigonometric function \(f\) over the specified interval, stating where \(f\) is increasing. decreasing, concave up, and concave down, and stating the \(x\) coordinates of all inflection points. Confirm that your results are consistent with the graph of \(f\) generated with a graphing utility. $$f(x)=2 x+\cot x ;(0, \pi)$$

5 step solution

Problem 28

Give a complete graph of the function, and identify the location of all critical points and inflection poir s. Check your work with a graphing utility. $$4 x-3 x^{4 / 3}$$

5 step solution

Problem 28

Use any method to find the relative extrema of the function \(f\). $$f(x)=2 x+x^{2 / 3}$$

4 step solution

Problem 29

Analyze the trigonometric function \(f\) over the specified interval, stating where \(f\) is increasing. decreasing, concave up, and concave down, and stating the \(x\) coordinates of all inflection points. Confirm that your results are consistent with the graph of \(f\) generated with a graphing utility. $$f(x)=\sin x \cos x ;[0, \pi]$$

6 step solution

Problem 29

Give a complete graph of the function, and identify the location of all critical points and inflection poir s. Check your work with a graphing utility. $$x \sqrt{3-x}$$

7 step solution

Problem 29

Use any method to find the relative extrema of the function \(f\). $$f(x)=\frac{x^{2}}{x^{2}+1}$$

5 step solution

Problem 30

Analyze the trigonometric function \(f\) over the specified interval, stating where \(f\) is increasing. decreasing, concave up, and concave down, and stating the \(x\) coordinates of all inflection points. Confirm that your results are consistent with the graph of \(f\) generated with a graphing utility. $$f(x)=\cos ^{2} x-2 \sin x ;[0,2 \pi]$$

7 step solution

Problem 30

Give a complete graph of the function, and identify the location of all critical points and inflection poir s. Check your work with a graphing utility. $$4 x^{1 / 3}-x^{4 / 3}$$

5 step solution

Problem 30

Use any method to find the relative extrema of the function \(f\). $$f(x)=\frac{x}{x+2}$$

4 step solution

Problem 31

In each part sketch a continuous curve \(y=f(x)\) with the stated properties. (a) \(f(2)=4, f^{\prime}(2)=0, f^{\prime \prime}(x)>0\) for all \(x\) (b) \(f(2)=4, f^{\prime}(2)=0, f^{\prime \prime}(x)<0\) for \(x<2, f^{\prime \prime}(x)>0\) for \(x>2\) (c) \(f(2)=4, f^{\prime \prime}(x)<0\) for \(x \neq 2\) and \(\lim _{x \rightarrow 2^{+}} f^{\prime}(x)=+\infty\) \(\lim _{x \rightarrow 2^{-}} f^{\prime}(x)=-\infty\)

6 step solution

Problem 31

Give a complete graph of the function, and identify the location of all critical points and inflection poir s. Check your work with a graphing utility. $$\frac{8(\sqrt{x}-1)}{x}$$

5 step solution

Problem 31

Use any method to find the relative extrema of the function \(f\). $$f(x)=\ln \left(1+x^{2}\right)$$

3 step solution

Problem 32

In each part sketch a continuous curve \(y=f(x)\) with the stated properties. (a) \(f(2)=4, \quad f^{\prime}(2)=0, \quad f^{\prime \prime}(x)<0\) for all \(x\) (b) \(f(2)=4, f^{\prime}(2)=0, f^{\prime \prime}(x)>0\) for \(x<2, f^{\prime \prime}(x)<0\) for \(x>2\) (c) \(f(2)=4, \quad f^{\prime \prime}(x)>0\) for \(x \neq 2\) and \(\lim _{x \rightarrow 2^{+}} f^{\prime}(x)=-\infty$$\lim _{x \rightarrow 2^{-}} f^{\prime}(x)=+\infty\)

6 step solution

Problem 32

Use any method to find the relative extrema of the function \(f\). $$f(x)=x^{2} e^{x}$$

4 step solution

Problem 33

In each part, assume that \(a\) is a constant and find the inflection points, if any. (a) \(f(x)=(x-a)^{3}\) (b) \(f(x)=(x-a)^{4}\)

6 step solution

Problem 33

Give a complete graph of the function, and identify the location of all relative extrema and inflection points. Check your work with a graphing utility. $$x+\sin x$$

6 step solution

Problem 33

Use any method to find the relative extrema of the function \(f\). $$f(x)=\left|x^{2}-4\right|$$

4 step solution

Problem 34

Give a complete graph of the function, and identify the location of all relative extrema and inflection points. Check your work with a graphing utility. $$x-\cos x$$

7 step solution

Problem 34

Use any method to find the relative extrema of the function \(f\). $$f(x)=\left\\{\begin{array}{ll} 9-x, & x \leq 3 \\\x^{2}-3, & x>3\end{array}\right.$$

5 step solution

Problem 35

If \(f\) is increasing on an interval \([0, b),\) then it follows from Definition 5.1.1 that \(f(0)0,\) and confirm the inequality with a graphing utility. [Hint: Show that the function \(\left.f(x)=1+\frac{1}{3} x-\sqrt[3]{1+x} \text { is increasing on }[0,+\infty) .\right]\)

5 step solution

Problem 35

Find the relative extrema in the interval \(0

5 step solution

Problem 35

Give a complete graph of the function, and identify the location of all relative extrema and inflection points. Check your work with a graphing utility. $$\sin x+\cos x$$

7 step solution

Problem 36

If \(f\) is increasing on an interval \([0, b),\) then it follows from Definition 5.1.1 that \(f(0)

6 step solution

Problem 36

Find the relative extrema in the interval \(0

5 step solution

Problem 36

Give a complete graph of the function, and identify the location of all relative extrema and inflection points. Check your work with a graphing utility. $$\sqrt{3} \cos x+\sin x$$

7 step solution

Problem 37

Find the relative extrema in the interval \(0

4 step solution

Problem 37

Give a complete graph of the function, and identify the location of all relative extrema and inflection points. Check your work with a graphing utility. $$\sin ^{2} x, \quad 0 \leq x \leq 2 \pi$$

7 step solution

Problem 38

If \(f\) is increasing on an interval \([0, b),\) then it follows from Definition 5.1.1 that \(f(0)

6 step solution

Problem 38

Find the relative extrema in the interval \(0< x <2 \pi,\) and confirm that your results are consistent with the graph of \(f\) generated with a graphing utility. $$f(x)=\frac{\sin x}{2-\cos x}$$

6 step solution

Problem 38

Give a complete graph of the function, and identify the location of all relative extrema and inflection points. Check your work with a graphing utility. $$x \tan x, \quad-\pi / 2

5 step solution

Problem 39

Use a graphing utility to generate the graphs of \(f^{\prime}\) and \(f^{\prime \prime}\) over the stated interval; then use those graphs to estimate the \(x\) -coordinates of the inflection points of \(f\), the intervals on which \(f\) is concave up or down, and the intervals on which \(f\) is increasing or decreasing. Check your estimates by graphing \(f\). $$f(x)=x^{4}-24 x^{2}+12 x, \quad-5 \leq x \leq 5$$

5 step solution

Problem 39

Use a graphing utility to make a conjecture about the relative extrema of \(f,\) and then check your conjecture using either the first or second derivative test. $$f(x)=x \ln x$$

5 step solution

Problem 40

Use a graphing utility to generate the graphs of \(f^{\prime}\) and \(f^{\prime \prime}\) over the stated interval; then use those graphs to estimate the \(x\) -coordinates of the inflection points of \(f\), the intervals on which \(f\) is concave up or down, and the intervals on which \(f\) is increasing or decreasing. Check your estimates by graphing \(f\). $$f(x)=\frac{1}{1+x^{2}}, \quad-5 \leq x \leq 5$$

5 step solution

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