Chapter 13

A Graphical Approach to Precalculus with Limits · 250 exercises

Problem 1

Let \(f(x)=2 x+1, x_{1}=0, x_{2}=2, x_{3}=4, x_{4}=6,\) and \(\Delta x=2\) (a) Find \(\sum_{i=1}^{4} f\left(x_{i}\right) \Delta x\) (b) The sum in part (a) approximates a definite integral by using rectangles. The height of each rectangle is given by the value of the function at the left endpoint. Write the definite integral that the sum approximates.

3 step solution

Problem 1

Determine each limit. Refer to the accompanying graph of \(y=f(x)\) when it is given. Do not use a calculator. (a) \(\lim _{x \rightarrow 2^{+}} f(x)\) (b) \(\lim _{x \rightarrow 2^{-}} f(x)\) where \(f(x)=\left\\{\begin{array}{ll}x & \text { if } x<2 \\ 3 & \text { if } x=2 \\ 4 & \text { if } x>2\end{array}\right.\) (GRAPH CANNOT COPY).

4 step solution

Problem 1

Let \(\lim _{x \rightarrow 4} f(x)=16\) and \(\lim _{x \rightarrow 4} g(x)=8 .\) Use the limit rules to find each limit. Do not use a calculator. $$\lim _{x \rightarrow 4}[f(x)-g(x)]$$

3 step solution

Problem 1

Tell whether each statement is true or false. If a function \(f\) is defined at \(x=a,\) then \(\lim f(x)\) is always equal to \(f(a)\)

4 step solution

Problem 2

Use the midpoint rule with \(n=4\) to approximate the area above the \(x\) -axis bounded by the graph of $$f(x)=\sqrt{16-x^{2}}$$ in the first quadrant.

6 step solution

Problem 2

Let \(\lim _{x \rightarrow 4} f(x)=16\) and \(\lim _{x \rightarrow 4} g(x)=8 .\) Use the limit rules to find each limit. Do not use a calculator. $$\lim _{x \rightarrow 4}[g(x) \cdot f(x)]$$

5 step solution

Problem 2

Tell whether each statement is true or false. If \(\lim f(x)\) does not exist, then \(f(x)\) necessarily approaches one value as \(x\) approaches \(a\) from the left and a different value as \(x\) approaches \(a\) from the right.

5 step solution

Problem 3

Approximate the area under the graph of \(f(x)\) and above the \(x\) -axis, using each of the following methods with \(n=4\). (a) Use left endpoints. (b) Use right endpoints. (c) Average the answers in parts ( \(a\) ) and ( \(b\) ). (d) Use midpoints. \(f(x)=3 x+2\) from \(x=1\) to \(x=5\)

5 step solution

Problem 3

Determine each limit. Refer to the accompanying graph of \(y=f(x)\) when it is given. Do not use a calculator. (a) \(\lim _{x \rightarrow 3^{+}} f(x)\) (b) \(\lim _{x \rightarrow 3^{-}} f(x)\) where \(f(x)=\frac{x}{5(3-x)^{3}}\) (GRAPH CANNOT COPY).

4 step solution

Problem 3

Let \(\lim _{x \rightarrow 4} f(x)=16\) and \(\lim _{x \rightarrow 4} g(x)=8 .\) Use the limit rules to find each limit. Do not use a calculator. $$\lim _{x \rightarrow 4} \frac{f(x)}{g(x)}$$

4 step solution

Problem 3

Tell whether each statement is true or false. If \(\lim _{x \rightarrow 1} f(x)=5,\) then 1 must be in the domain of \(f(x)\)

5 step solution

Problem 4

Approximate the area under the graph of \(f(x)\) and above the \(x\) -axis, using each of the following methods with \(n=4\). (a) Use left endpoints. (b) Use right endpoints. (c) Average the answers in parts ( \(a\) ) and ( \(b\) ). (d) Use midpoints. $$f(x)=x+5 \text { from } x=2 \text { to } x=4$$

5 step solution

Problem 4

Let \(\lim _{x \rightarrow 4} f(x)=16\) and \(\lim _{x \rightarrow 4} g(x)=8 .\) Use the limit rules to find each limit. Do not use a calculator. $$\lim _{x \rightarrow 4}\left[\log _{2} f(x)\right]$$

5 step solution

Problem 4

Tell whether each statement is true or false. If \(\lim _{x \rightarrow 1} f(x)=5,\) then 1 must be in the domain of \(f(x)\)

3 step solution

Problem 5

Approximate the area under the graph of \(f(x)\) and above the \(x\) -axis, using each of the following methods with \(n=4\). (a) Use left endpoints. (b) Use right endpoints. (c) Average the answers in parts ( \(a\) ) and ( \(b\) ). (d) Use midpoints. $$f(x)=x+2 \text { from } x=0 \text { to } x=4$$

5 step solution

Problem 5

Find the slope of the tangent line to each curve when \(x\) has the given value. Do not use a calculator. $$f(x)=x^{2} ; x=4$$

3 step solution

Problem 5

Let \(\lim _{x \rightarrow 4} f(x)=16\) and \(\lim _{x \rightarrow 4} g(x)=8 .\) Use the limit rules to find each limit. Do not use a calculator. $$\lim _{x \rightarrow 4} \sqrt{f(x)}$$

5 step solution

Problem 6

Approximate the area under the graph of \(f(x)\) and above the \(x\) -axis, using each of the following methods with \(n=4\). (a) Use left endpoints. (b) Use right endpoints. (c) Average the answers in parts ( \(a\) ) and ( \(b\) ). (d) Use midpoints. $$f(x)=3+x \text { from } x=1 \text { to } x=3$$

5 step solution

Problem 6

Find the slope of the tangent line to each curve when \(x\) has the given value. Do not use a calculator. $$f(x)=x^{2}+5 ; x=2$$

5 step solution

Problem 6

Determine each limit. Refer to the accompanying graph of \(y=f(x)\) when it is given. Do not use a calculator. (a) \(\lim _{x \rightarrow 1^{+}} f(x)\) (b) \(\lim _{x \rightarrow 1^{-}} f(x)\) where \(f(x)=\frac{2 x}{(x-1)^{2}}\) (GRAPH CANNOT COPY).

3 step solution

Problem 6

Let \(\lim _{x \rightarrow 4} f(x)=16\) and \(\lim _{x \rightarrow 4} g(x)=8 .\) Use the limit rules to find each limit. Do not use a calculator. $$\lim _{x \rightarrow 4}[1+f(x)]^{2}$$

3 step solution

Problem 6

Tell whether each statement is true or false. If \(\lim _{x \rightarrow a} f(x)=b,\) then \(|f(x)-b|<0.0001\) for some value of \(x\) near \(a\)

4 step solution

Problem 7

Approximate the area under the graph of \(f(x)\) and above the \(x\) -axis, using each of the following methods with \(n=4\). (a) Use left endpoints. (b) Use right endpoints. (c) Average the answers in parts ( \(a\) ) and ( \(b\) ). (d) Use midpoints. $$f(x)=x^{2} \text { from } x=1 \text { to } x=5$$

5 step solution

Problem 7

Find the slope of the tangent line to each curve when \(x\) has the given value. Do not use a calculator. $$f(x)=-4 x^{2}+11 x ; x=-2$$

4 step solution

Problem 7

Let \(\lim _{x \rightarrow 4} f(x)=16\) and \(\lim _{x \rightarrow 4} g(x)=8 .\) Use the limit rules to find each limit. Do not use a calculator. $$\lim _{x \rightarrow 4} 2^{g(x)}$$

3 step solution

Problem 7

Determine each limit. Refer to the accompanying graph of \(y=f(x)\) when it is given. Do not use a calculator. $$\lim _{x \rightarrow 5^{+}}(3 x-5)$$

4 step solution

Problem 8

Approximate the area under the graph of \(f(x)\) and above the \(x\) -axis, using each of the following methods with \(n=4\). (a) Use left endpoints. (b) Use right endpoints. (c) Average the answers in parts ( \(a\) ) and ( \(b\) ). (d) Use midpoints. $$f(x)=-x^{2}+4 \text { from } x=-2 \text { to } x=2$$

5 step solution

Problem 8

Find the slope of the tangent line to each curve when \(x\) has the given value. Do not use a calculator. $$f(x)=6 x^{2}-4 x, x=-1$$

4 step solution

Problem 8

Let \(\lim _{x \rightarrow 4} f(x)=16\) and \(\lim _{x \rightarrow 4} g(x)=8 .\) Use the limit rules to find each limit. Do not use a calculator. $$\lim _{x \rightarrow 4} \sqrt[3]{g(x)}$$

4 step solution

Problem 8

Determine each limit. Refer to the accompanying graph of \(y=f(x)\) when it is given. Do not use a calculator. $$\lim _{x \rightarrow-4^{-}} x^{3}$$

4 step solution

Problem 9

Approximate the area under the graph of \(f(x)\) and above the \(x\) -axis, using each of the following methods with \(n=4\). (a) Use left endpoints. (b) Use right endpoints. (c) Average the answers in parts ( \(a\) ) and ( \(b\) ). (d) Use midpoints. $$f(x)=e^{x}-1 \text { from } x=0 \text { to } x=4$$

5 step solution

Problem 9

Find the slope of the tangent line to each curve when \(x\) has the given value. Do not use a calculator. $$f(x)=-\frac{2}{x} ; x=4$$

3 step solution

Problem 9

Let \(\lim _{x \rightarrow 4} f(x)=16\) and \(\lim _{x \rightarrow 4} g(x)=8 .\) Use the limit rules to find each limit. Do not use a calculator. $$\lim _{x \rightarrow 4} \frac{f(x)+g(x)}{2 g(x)}$$

4 step solution

Problem 9

Determine each limit. Refer to the accompanying graph of \(y=f(x)\) when it is given. Do not use a calculator. $$\lim _{x \rightarrow 7^{-}} 100$$

3 step solution

Problem 10

Approximate the area under the graph of \(f(x)\) and above the \(x\) -axis, using each of the following methods with \(n=4\). (a) Use left endpoints. (b) Use right endpoints. (c) Average the answers in parts ( \(a\) ) and ( \(b\) ). (d) Use midpoints. $$f(x)=e^{x}+1 \text { from } x=-2 \text { to } x=2$$

5 step solution

Problem 10

Find the slope of the tangent line to each curve when \(x\) has the given value. Do not use a calculator. $$f(x)=\frac{6}{x} ; x=-1$$

3 step solution

Problem 10

Let \(\lim _{x \rightarrow 4} f(x)=16\) and \(\lim _{x \rightarrow 4} g(x)=8 .\) Use the limit rules to find each limit. Do not use a calculator. $$\lim _{x \rightarrow 4} \frac{5 g(x)+2}{1-f(x)}$$

4 step solution

Problem 11

Approximate the area under the graph of \(f(x)\) and above the \(x\) -axis, using each of the following methods with \(n=4\). (a) Use left endpoints. (b) Use right endpoints. (c) Average the answers in parts ( \(a\) ) and ( \(b\) ). (d) Use midpoints. $$f(x)=\frac{1}{x} \text { from } x=1 \text { to } x=5$$

5 step solution

Problem 11

Find the slope of the tangent line to each curve when \(x\) has the given value. Do not use a calculator. $$f(x)=-3 \sqrt{x} ; x=1$$

5 step solution

Problem 11

Determine each limit, if it exists. $$\lim _{x \rightarrow-3} 7$$

3 step solution

Problem 11

Determine each limit. Refer to the accompanying graph of \(y=f(x)\) when it is given. Do not use a calculator. $$\lim _{x \rightarrow-3^{-}} \sqrt{x+3}$$

4 step solution

Problem 12

Approximate the area under the graph of \(f(x)\) and above the \(x\) -axis, using each of the following methods with \(n=4\). (a) Use left endpoints. (b) Use right endpoints. (c) Average the answers in parts ( \(a\) ) and ( \(b\) ). (d) Use midpoints. $$f(x)=\frac{2}{x} \text { from } x=1 \text { to } x=9$$

5 step solution

Problem 12

Find the slope of the tangent line to each curve when \(x\) has the given value. Do not use a calculator. $$f(x)=x^{3} ; x=1$$

4 step solution

Problem 12

Determine each limit, if it exists. $$\lim _{x \rightarrow 6}(-5)$$

2 step solution

Problem 12

Determine each limit. Refer to the accompanying graph of \(y=f(x)\) when it is given. Do not use a calculator. $$\lim _{x \rightarrow 2^{-}} \sqrt{2-x}$$

4 step solution

Problem 13

Consider the region below \(f(x)=\frac{x}{2},\) above the \(x\) -axis, and between \(x=0\) and \(x=4 .\) Let \(x_{i}\) be the midpoint of the \(i\) th subinterval. (a) Approximate the area of the region, using four rectangles. (b) Find \(\int_{0}^{4} f(x) d x\) by using the formula for the area of a triangle.

7 step solution

Problem 13

Find the slope of the tangent line to each curve when \(x\) has the given value. Do not use a calculator. $$f(x)=2 x^{3} ; x=1$$

4 step solution

Problem 13

Determine each limit, if it exists. $$\lim _{x \rightarrow \pi} x$$

3 step solution

Problem 13

Determine each limit. Refer to the accompanying graph of \(y=f(x)\) when it is given. Do not use a calculator. $$\lim _{x \rightarrow 0^{-}} \frac{|x|}{x}$$

3 step solution

Problem 14

Find \(\int_{0}^{5}(5-x) d x\) by using the formula for the area of a triangle.

5 step solution

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