Chapter 11
Precalculus · 202 exercises
Problem 1
Fill in each blank with the appropriate word or phrase. The slope of a line drawn tangent to the graph of any function \(f(x)\) can be found by taking the limit of the _____ quotient for \(f,\) as \(h\) approaches zero.
4 step solution
Problem 2
Fill in each blank with the appropriate word or phrase. Carefully reread the section, if necessary. $$\lim _{x \rightarrow c} g(x)=L$$ means that values of \(g(x)\) can be made ____________ to \(L,\) by taking values of ____________ sufficiently close to ____________
4 step solution
Problem 3
Fill in each blank with the appropriate word or phrase. In order to obtain a better approximation for the area under a curve, we can use narrower (and thus more) _____ in our computation.
4 step solution
Problem 4
Fill in each blank with the appropriate word or phrase. As we let the number of approximating rectangles increase without bound, the resulting limit gives \(a(n)\) _____ value for the area under the curve.
4 step solution
Problem 5
Discuss/Explain the relationship between the difference quotient and the formula for finding the slope of a line given two points.
4 step solution
Problem 5
Discuss/Explain the relationship between the horizontal asymptote of a rational function \(f\), and \(\lim _{x \rightarrow \infty} f(x)\).
4 step solution
Problem 5
Discuss/Explain why \(\lim _{x \rightarrow 3} g(x)=5\) for \(g(x)=\) \(\frac{x^{2}-x-6}{x-3},\) but \(g(3) \neq 5 .\) Can we redefine \(g(x)\) to create a piecewise-defined function where \(\lim _{x \rightarrow 3} g(x)=g(3) ?\)
6 step solution
Problem 6
Discuss/Explain how the three different types of discontinuities appear on the graph of a function.
3 step solution
Problem 6
Discuss/Explain why \(\lim _{x \rightarrow 1} f(x)\) does not exist for \(f(x)=\frac{x^{2}-x}{\sqrt{(x-1)^{2}}},\) even though the left-hand limit and the right-hand limit do exist.
5 step solution
Problem 7
Two model rockets are launched at a gathering of the National Association of Rocketry (NAR: www.nar.org). Frank's Apollo II motor burns out at a height of \(500 \mathrm{m},\) at which point the rocket has a velocity of 88.2 meters per second (m/sec). His rocket's height in meters, \(t\) sec after engine burnout, is given by \(f(t)=500+88.2 t-4.9 t^{2}\) Gwen's Icarus Alpha motor burns out at a height of \(600 \mathrm{m}\) at which point the rocket has a velocity of \(78.4 \mathrm{m} / \mathrm{sec} .\) Her rocket's height in meters, \(t\) sec after burnout, is given by \(g(t)=600+78.4 t-4.9 t^{2}\). Find the limit of the difference quotient for \(f,\) to obtain a function \(f(t)\) that represents the instantaneous velocity at time \(t\).
5 step solution
Problem 7
Write each of the following statements using limit notation. As \(n\) approaches \(\infty, V_{n}\) approaches \(\frac{4}{3} \pi r^{3}\)
3 step solution
Problem 8
Write each of the following statements using limit notation. As \(n\) approaches \(\infty, A_{n}\) approaches \(\frac{a}{3} x^{3}+\frac{b}{2} x^{2}+c x+d\)
2 step solution
Problem 9
Two model rockets are launched at a gathering of the National Association of Rocketry (NAR: www.nar.org). Frank's Apollo II motor burns out at a height of \(500 \mathrm{m},\) at which point the rocket has a velocity of 88.2 meters per second (m/sec). His rocket's height in meters, \(t\) sec after engine burnout, is given by \(f(t)=500+88.2 t-4.9 t^{2}\) Gwen's Icarus Alpha motor burns out at a height of \(600 \mathrm{m}\) at which point the rocket has a velocity of \(78.4 \mathrm{m} / \mathrm{sec} .\) Her rocket's height in meters, \(t\) sec after burnout, is given by \(g(t)=600+78.4 t-4.9 t^{2}\). Find the limit of the difference quotient for \(g\), to obtain a function \(g(t)\) that represents the instantaneous velocity at time \(t\).
4 step solution
Problem 9
Write each of the following statements using limit notation. As \(t\) approaches \(-\infty, e^{/ n}\) approaches 0
5 step solution
Problem 10
Write each of the following statements using limit notation. As \(t\) approaches \(-\infty, \sin [g(t)]\) approaches 1
3 step solution
Problem 11
Two model rockets are launched at a gathering of the National Association of Rocketry (NAR: www.nar.org). Frank's Apollo II motor burns out at a height of \(500 \mathrm{m},\) at which point the rocket has a velocity of 88.2 meters per second (m/sec). His rocket's height in meters, \(t\) sec after engine burnout, is given by \(f(t)=500+88.2 t-4.9 t^{2}\) Gwen's Icarus Alpha motor burns out at a height of \(600 \mathrm{m}\) at which point the rocket has a velocity of \(78.4 \mathrm{m} / \mathrm{sec} .\) Her rocket's height in meters, \(t\) sec after burnout, is given by \(g(t)=600+78.4 t-4.9 t^{2}\). Use the result from Exercise 7 to find the maximum height of Frank's rocket. This occurs when \(v=0\).
6 step solution
Problem 11
Write each of the following statements using limit notation. As \(x\) increases without bound, \(\cos \left(\frac{1}{x}\right)\) approaches 1
4 step solution
Problem 12
Write each of the following statements using limit notation. As \(x\) decreases without bound, \(\frac{5 x^{2}-3}{2 x^{2}-x-1}\) approaches \(\frac{5}{2}\)
3 step solution
Problem 13
To replicate Galileo's famous test as to whether the velocity of a falling body depends on its weight, a science class is dropping bowling balls of different weights from an 11 -story building onto the lawn below. The ball's height in meters, \(t\) sec after it is, released, is modeled by \(d(t)=-4.9 t^{2}+44.1 .\) Find the limit of the difference quotient for \(d\), to obtain a function \(d(t)\) that represents the instantaneous velocity of the bowling ball at time \(t.\)
5 step solution
Problem 14
If an \(n\) -sided regular polygon is inscribed in a circle of radius \(r\), its perimeter is given by \(P=2 n r \sin \left(\frac{\pi}{n}\right) .\) For a circle with radius \(r=50 \mathrm{mm},\) determine the number of sides needed (to the nearest 25 ) for the perimeter of the polygon to approximate the circumference of the circle correct to two decimal places when rounded.
6 step solution
Problem 15
A rock climber's carabineer falls off her harness \(256 \mathrm{ft}\) above the floor of the Grand Canyon. It's height in feet, \(t\) sec after it falls, can be modeled by \(d(t)=-16 t^{2}+256 .\) Find the limit of the difference quotient for \(d\), to obtain a function \(d l(t)\) that represents the instantaneous velocity of the "biner" at time \(t.\)
5 step solution
Problem 16
One of the most famous and useful numbers in all of mathematics is the one defined as \(\lim _{x \rightarrow \infty}\left(1+\frac{1}{x}\right)^{x}=e\) Determine the smallest \(x\) to (the nearest 250 ) that can be used to approximate the value of \(e\) to three decimal places.
6 step solution
Problem 17
Find the limit of the difference quotient for each function \(f(x)\) given, to obtain a function \(f(x)\) that represents the instantaneous rate of change at \(x\) for each function. $$f(x)=\frac{1}{2} x+5$$
5 step solution
Problem 17
Evaluate the following limits using direct substitution, if possible. If not possible, state why. $$\lim _{x \rightarrow-3} 2 x^{2}-5 x+3$$
6 step solution
Problem 17
Write each of the following statements using limit notation. As \(t\) approaches \(5, s_{t}\) approaches \(5 r\)
3 step solution
Problem 18
Find the limit of the difference quotient for each function \(f(x)\) given, to obtain a function \(f(x)\) that represents the instantaneous rate of change at \(x\) for each function. $$f(x)=x^{2}-3 x$$
8 step solution
Problem 18
Evaluate the following limits using direct substitution, if possible. If not possible, state why. $$\lim _{x \rightarrow-2} 3 x^{2}-5 x-2$$
6 step solution
Problem 18
Write each of the following statements using limit notation. As \(t\) approaches \(-3, d_{t}\) approaches \(\sqrt{9+r^{2}}\)
3 step solution
Problem 19
Find the limit of the difference quotient for each function \(f(x)\) given, to obtain a function \(f(x)\) that represents the instantaneous rate of change at \(x\) for each function. $$f(x)=x^{3}$$
5 step solution
Problem 19
Evaluate the following limits using direct substitution, if possible. If not possible, state why. $$\lim _{x \rightarrow 5} \sqrt{3 x-19}$$
5 step solution
Problem 19
Write each of the following statements using limit notation. As \(x\) approaches \(a, \tan ^{-1}[g(x)]\) approaches \(\frac{\pi}{3}\)
3 step solution
Problem 20
Find the limit of the difference quotient for each function \(f(x)\) given, to obtain a function \(f(x)\) that represents the instantaneous rate of change at \(x\) for each function. $$f(x)=\frac{1}{x}$$
6 step solution
Problem 20
Evaluate the following limits using direct substitution, if possible. If not possible, state why. $$\lim _{x \rightarrow-6} \sqrt{x^{2}+7 x}$$
4 step solution
Problem 20
Write each of the following statements using limit notation. As \(x\) approaches \(b, \csc ^{2}[f(x)]\) approaches \(\frac{4}{3}\)
3 step solution
Problem 21
The population of a small town can be modeled by the function \(p(t)=1.2 \sqrt{t}+40,\) where \(p\) is measured in thousands and \(t\) is the number of years after \(2008 .\) Find the limit of the difference quotient for \(p\) to obtain a function \(p(t)\) that represents the instantaneous rate of change of population at time \(t.\)
7 step solution
Problem 21
Evaluate the following limits using direct substitution, if possible. If not possible, state why. $$\lim _{x \rightarrow 2} \frac{x^{2}}{5 x-2}$$
4 step solution
Problem 21
Write each of the following statements using limit notation. As \(x \rightarrow-3, \frac{x+3}{x^{2}-9}\) approaches \(-\frac{1}{6}\)
3 step solution
Problem 22
Evaluate the following limits using direct substitution, if possible. If not possible, state why. $$\lim _{x \rightarrow 8} \frac{2 x-5}{x^{2}-5 x}$$
2 step solution
Problem 22
Write each of the following statements using limit notation. As \(x \rightarrow \pi, \frac{\sin x}{\cos \left(\frac{x}{2}\right)}\) approaches 2.
2 step solution
Problem 23
The number of bacteria in a person's body, after they begin a regimen of antibiotics, can be modeled by the function \(b(t)=6-\sqrt{t},\) where \(b\) is measured in tens of thousands and \(t\) is the number of hours after the first dose. Find the limit of the difference quotient for \(b\) to obtain a function \(b(t)\) that represents the instantaneous rate of change of number of bacteria at time \(t.\)
6 step solution
Problem 23
Evaluate the following limits using direct substitution, if possible. If not possible, state why. $$\lim _{x \rightarrow-1} \frac{x+1}{x^{2}-1}$$
4 step solution
Problem 23
Use a table of values to evaluate each function as \(x\) approaches the value indicated. If the function seems to approach a limiting value, write the relationship in words and using the limit notation. $$p(x)=\cos x+\sin \left(\frac{3 x}{2}\right) ; x \rightarrow \pi$$
5 step solution
Problem 24
Evaluate the following limits using direct substitution, if possible. If not possible, state why. $$\lim _{x \rightarrow-2} \frac{4-x^{2}}{x^{2}+5 x+6}$$
4 step solution
Problem 24
Use a table of values to evaluate each function as \(x\) approaches the value indicated. If the function seems to approach a limiting value, write the relationship in words and using the limit notation. $$q(x)=\tan x+3 \sin 2 x ; x \rightarrow \frac{\pi}{4}$$
5 step solution
Problem 25
Find the limit of the difference quotient of the given function to obtain a function that represents the slope of a line drawn tangent to the curve at \(x.\) $$f(x)=\frac{2}{x-1}$$
5 step solution
Problem 25
Evaluate the following limits using direct substitution, if possible. If not possible, state why. $$\lim _{x \rightarrow-5} \sqrt{x^{2}-6 x}$$
4 step solution
Problem 25
Use a table of values to evaluate each function as \(x\) approaches the value indicated. If the function seems to approach a limiting value, write the relationship in words and using the limit notation. $$v(x)=\frac{\cos \left(\frac{\pi}{x}\right)}{\sin (\pi x)} ; x \rightarrow 2$$
5 step solution
Problem 26
Find the limit of the difference quotient of the given function to obtain a function that represents the slope of a line drawn tangent to the curve at \(x.\) $$g(x)=\frac{3}{x+2}$$
5 step solution
Problem 26
Evaluate the following limits using direct substitution, if possible. If not possible, state why. $$\lim _{x \rightarrow 6} \sqrt{3 x-5}$$
5 step solution
Problem 26
Use a table of values to evaluate each function as \(x\) approaches the value indicated. If the function seems to approach a limiting value, write the relationship in words and using the limit notation. $$w(x)=\frac{\tan (x-2)}{x-2} ; x \rightarrow 2$$
5 step solution