Chapter 13

Precalculus Mathematics for Calculus · 131 exercises

Problem 15

Evaluate the limit if it exists. $$\lim _{t \rightarrow-3} \frac{t^{2}-9}{2 t^{2}+7 t+3}$$

4 step solution

Problem 15

Find the limit. $$\lim _{x \rightarrow-\infty}\left(\frac{x-1}{x+1}+6\right)$$

5 step solution

Problem 15

Find the derivative of the function at the given number. $$f(x)=1-3 x^{2} \text { at } 2$$

6 step solution

Problem 16

Use a table of values to estimate the value of the limit. Then use a graphing device to confirm your result graphically. $$\lim _{x \rightarrow 0} \frac{\tan 2 x}{\tan 3 x}$$

4 step solution

Problem 16

Find the area of the region that lies under the graph of \(f\) over the given interval. $$f(x)=x+x^{2}, \quad 0 \leq x \leq 1$$

5 step solution

Problem 16

Evaluate the limit if it exists. $$\lim _{h \rightarrow 0} \frac{\sqrt{1+h}-1}{h}$$

5 step solution

Problem 16

Find the limit. $$\lim _{x \rightarrow-\infty}\left(\frac{3-x}{3+x}-2\right)$$

5 step solution

Problem 16

Find the derivative of the function at the given number. $$f(x)=2-3 x+x^{2} \quad \text { at }-1$$

4 step solution

Problem 17

Find the area of the region that lies under the graph of \(f\) over the given interval. $$f(x)=x^{3}+2, \quad 0 \leq x \leq 5$$

5 step solution

Problem 17

Evaluate the limit if it exists. $$\lim _{h \rightarrow 0} \frac{(2+h)^{3}-8}{h}$$

5 step solution

Problem 17

Find the derivative of the function at the given number. $$g(x)=x^{4} \quad \text { at } 1$$

2 step solution

Problem 18

Find the area of the region that lies under the graph of \(f\) over the given interval. $$f(x)=4 x^{3}, \quad 2 \leq x \leq 5$$

5 step solution

Problem 18

Evaluate the limit if it exists. $$\lim _{x \rightarrow 2} \frac{x^{4}-16}{x-2}$$

4 step solution

Problem 18

Find the derivative of the function at the given number. $$g(x)=2 x^{2}+x^{3} \quad \text { at } 1$$

6 step solution

Problem 19

Find the area of the region that lies under the graph of \(f\) over the given interval. $$f(x)=x+6 x^{2}, \quad 1 \leq x \leq 4$$

5 step solution

Problem 19

Evaluate the limit if it exists. $$\lim _{x \rightarrow 7} \frac{\sqrt{x+2}-3}{x-7}$$

5 step solution

Problem 19

Use a table of values to estimate the limit. Then use a graphing device to confirm your result graphically. $$\lim _{x \rightarrow-\infty} \frac{\sqrt{x^{2}+4 x}}{4 x+1}$$

4 step solution

Problem 19

Find the derivative of the function at the given number. $$F(x)=\frac{1}{\sqrt{x}} \quad \text { at } 4$$

4 step solution

Problem 20

Find the area of the region that lies under the graph of \(f\) over the given interval. $$f(x)=20-2 x^{2}, \quad 2 \leq x \leq 3$$

6 step solution

Problem 20

Evaluate the limit if it exists. $$\lim _{h \rightarrow 0} \frac{(3+h)^{-1}-3^{-1}}{h}$$

6 step solution

Problem 20

Use a table of values to estimate the limit. Then use a graphing device to confirm your result graphically. $$\lim _{x \rightarrow \infty}(\sqrt{9 x^{2}+x}-3 x)$$

6 step solution

Problem 20

Find the derivative of the function at the given number. $$G(x)=1+2 \sqrt{x} \text { at } 4$$

5 step solution

Problem 21

Use a graphing device to determine whether the limit exists. If the limit exists, estimate its value to two decimal places. $$\lim _{x \rightarrow 1} \frac{x^{3}+x^{2}+3 x-5}{2 x^{2}-5 x+3}$$

6 step solution

Problem 21

When we approximate areas using rectangles as in Example \(1,\) then the more rectangles we use, the more accurate the answer. The following TI- 83 program finds the approximate area under the graph of \(f\) on the interval \([a, b]\) using \(n\) rectangles. To use the program, first store the function \(f\) in \(Y_{1}\). The program prompts you to enter \(\mathrm{N}\), the number of rectangles, and \(\mathrm{A}\) and \(\mathrm{B}\), the endpoints of the interval. (a) Approximate the area under the graph of \(f(x)=x^{5}+2 x+3\) on \([1,3],\) using \(10,20\) and 100 rectangles. (b) Approximate the area under the graph of \(f\) on the given interval, using 100 rectangles. (i) \(f(x)=\sin x, \quad\) on \([0, \pi]\) (ii) \(f(x)=e^{-x^{2}}, \quad\) on \([-1,1]\) (GRAPH CANT COPY)

8 step solution

Problem 21

Evaluate the limit if it exists. $$\lim _{x \rightarrow-4} \frac{\frac{1}{4}+\frac{1}{x}}{4+x}$$

4 step solution

Problem 21

Use a table of values to estimate the limit. Then use a graphing device to confirm your result graphically. $$\lim _{x \rightarrow \infty} \frac{x^{5}}{e^{x}}$$

5 step solution

Problem 21

Find \(f^{\prime}(a),\) where \(a\) is in the domain of \(f .\) $$f(x)=x^{2}+2 x$$

2 step solution

Problem 22

Use a graphing device to determine whether the limit exists. If the limit exists, estimate its value to two decimal places. $$\lim _{x \rightarrow 0} \frac{x^{2}}{\cos 5 x-\cos 4 x}$$

4 step solution

Problem 22

Evaluate the limit if it exists. $$\lim _{t \rightarrow 0}\left(\frac{1}{t}-\frac{1}{t^{2}+t}\right)$$

5 step solution

Problem 22

Use a table of values to estimate the limit. Then use a graphing device to confirm your result graphically. $$\lim _{x \rightarrow \infty}\left(1+\frac{2}{x}\right)^{3 x}$$

5 step solution

Problem 22

Find \(f^{\prime}(a),\) where \(a\) is in the domain of \(f .\) $$f(x)=-\frac{1}{x^{2}}$$

3 step solution

Problem 23

Find the limit and use a graphing device to confirm your result graphically. $$\lim _{x \rightarrow 1} \frac{x^{2}-1}{\sqrt{x}-1}$$

6 step solution

Problem 23

If the sequence is convergent, find its limit. If it is divergent, explain why. $$a_{n}=\frac{1+n}{n+n^{2}}$$

5 step solution

Problem 23

Find \(f^{\prime}(a),\) where \(a\) is in the domain of \(f .\) $$f(x)=\frac{x}{x+1}$$

6 step solution

Problem 24

Use a graphing device to determine whether the limit exists. If the limit exists, estimate its value to two decimal places. $$\lim _{x \rightarrow 2} \frac{x^{3}+6 x^{2}-5 x+1}{x^{3}-x^{2}-8 x+12}$$

6 step solution

Problem 24

Find the limit and use a graphing device to confirm your result graphically. $$\lim _{x \rightarrow 0} \frac{(4+x)^{3}-64}{x}$$

6 step solution

Problem 24

If the sequence is convergent, find its limit. If it is divergent, explain why. $$a_{n}=\frac{5 n}{n+5}$$

4 step solution

Problem 24

Find \(f^{\prime}(a),\) where \(a\) is in the domain of \(f .\) $$f(x)=\sqrt{x-2}$$

5 step solution

Problem 25

Use a graphing device to determine whether the limit exists. If the limit exists, estimate its value to two decimal places. $$\lim _{x \rightarrow 0} \cos \frac{1}{x}$$

4 step solution

Problem 25

Find the limit and use a graphing device to confirm your result graphically. $$\lim _{x \rightarrow-1} \frac{x^{2}-x-2}{x^{3}-x}$$

6 step solution

Problem 25

If the sequence is convergent, find its limit. If it is divergent, explain why. $$a_{n}=\frac{n^{2}}{n+1}$$

4 step solution

Problem 25

(a) If \(f(x)=x^{3}-2 x+4,\) find \(f^{\prime}(a)\) (b) Find equations of the tangent lines to the graph of \(f\) at the points whose \(x\) -coordinates are \(0,1,\) and 2 (c) Graph \(f\) and the three tangent lines.

4 step solution

Problem 26

Use a graphing device to determine whether the limit exists. If the limit exists, estimate its value to two decimal places. $$\lim _{x \rightarrow 0} \sin \frac{2}{x}$$

5 step solution

Problem 26

Find the limit and use a graphing device to confirm your result graphically. $$\lim _{x \rightarrow 1} \frac{x^{8}-1}{x^{5}-x}$$

5 step solution

Problem 26

If the sequence is convergent, find its limit. If it is divergent, explain why. $$a_{n}=\frac{n-1}{n^{3}+1}$$

5 step solution

Problem 26

(a) If \(g(x)=1 /(2 x-1),\) find \(g^{\prime}(a)\) (b) Find equations of the tangent lines to the graph of \(g\) at the points whose \(x\) -coordinates are \(-1,0,\) and 1 (c) Graph \(g\) and the three tangent lines.

5 step solution

Problem 27

(a) Estimate the value of $$\lim _{x \rightarrow 0} \frac{x}{\sqrt{1+3 x}-1}$$ by graphing the function \(f(x)=x /(\sqrt{1+3 x}-1)\) (b) Make a table of values of \(f(x)\) for \(x\) close to \(0,\) and guess the value of the limit. (c) Use the Limit Laws to prove that your guess is correct.

5 step solution

Problem 27

If the sequence is convergent, find its limit. If it is divergent, explain why. $$a_{n}=\frac{1}{3^{n}}$$

3 step solution

Problem 27

If a ball is thrown straight up with a velocity of \(40 \mathrm{ft} / \mathrm{s}\), its height (in feet) after \(t\) seconds is given by \(y=40 t-16 t^{2} .\) Find the instantaneous velocity when \(t=2\)

4 step solution

Problem 28

Use a graphing device to determine whether the limit exists. If the limit exists, estimate its value to two decimal places. $$\lim _{x \rightarrow 0} \frac{1}{1+e^{1 / x}}$$

5 step solution

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