Chapter 5

Precalculus: Functions and Graphs · 379 exercises

Problem 63

Graph the equation on the Interval \([-2,2]\), and describe the behavior of \(y\) as \(x \rightarrow 0^{-}\) and as \(x \rightarrow 0^{+}\) \(y=\sin \frac{1}{x}\)

6 step solution

Problem 63

A ship leaves port at 1: 00 P.M. and sails in the direction \(\mathrm{N} 34^{\circ} \mathrm{W}\) at a rate of \(24 \mathrm{mi} / \mathrm{hr}\). Another ship leaves port at 1: 30 p.M. and sails in the direction \(N 56^{\circ} \mathrm{E}\) at a rate of \(18 \mathrm{mi} / \mathrm{hr}\) (a) Approximately how far apart are the ships at 3: 00 P.M.? (b) What is the bearing, to the nearest degree, from the first ship to the second?

6 step solution

Problem 63

Find the intervals between \(-2 \pi\) and \(2 \pi\) on which the given function is (a) increasing or (b) decreasing. secant

5 step solution

Problem 63

Sketch the graph of the equation. $$y=2^{-x} \cos x$$

5 step solution

Problem 63

Verify the identity by transforming the lefthand side into the right-hand side. $$\sec \theta-\cos \theta=\tan \theta \sin \theta$$

6 step solution

Problem 64

Graph the equation on the Interval \([-2,2]\), and describe the behavior of \(y\) as \(x \rightarrow 0^{-}\) and as \(x \rightarrow 0^{+}\) \(y=|x| \sin \frac{1}{x}\)

4 step solution

Problem 64

Sketch the graph of the equation. $$y=e^{x} \sin x$$

7 step solution

Problem 64

Verify the identity by transforming the lefthand side into the right-hand side. $$\frac{\sin \theta+\cos \theta}{\cos \theta}=1+\tan \theta$$

5 step solution

Problem 65

An airplane flying at a speed of \(360 \mathrm{mi} / \mathrm{hr}\) flies from a point \(A\) in the direction \(137^{\circ}\) for 30 minutes and then flies in the direction \(227^{\circ}\) for 45 minutes. Approximate, to the nearest mile, the distance from the airplane to \(A\).

8 step solution

Problem 65

Graph the equation on the Interval \([-2,2]\), and describe the behavior of \(y\) as \(x \rightarrow 0^{-}\) and as \(x \rightarrow 0^{+}\) \(y=\frac{\sin 2 x}{x}\)

5 step solution

Problem 65

Find the intervals between \(-2 \pi\) and \(2 \pi\) on which the given function is (a) increasing or (b) decreasing. tangent

4 step solution

Problem 65

Sketch the graph of the equation. $$y=|x| \sin x$$

6 step solution

Problem 65

Verify the identity by transforming the lefthand side into the right-hand side. $$(\cot \theta+\csc \theta)(\tan \theta-\sin \theta)=\sec \theta-\cos \theta$$

4 step solution

Problem 66

An airplane flying at a speed of \(400 \mathrm{mi} / \mathrm{hr}\) flies from a point \(A\) in the direction \(153^{\circ}\) for 1 hour and then flies in the direction \(63^{\circ}\) for 1 hour. (a) In what direction does the plane need to fly in order to get back to point \(A ?\) (b) How long will it take to get back to point \(A ?\)

5 step solution

Problem 66

Graph the equation on the Interval \([-2,2]\), and describe the behavior of \(y\) as \(x \rightarrow 0^{-}\) and as \(x \rightarrow 0^{+}\) \(y=\frac{1-\cos 3 x}{x}\)

5 step solution

Problem 66

Find the intervals between \(-2 \pi\) and \(2 \pi\) on which the given function is (a) increasing or (b) decreasing. cotangent

4 step solution

Problem 66

Sketch the graph of the equation. $$y=|x| \cos x$$

5 step solution

Problem 66

Verify the identity by transforming the lefthand side into the right-hand side. $$\cot \theta+\tan \theta=\csc \theta \sec \theta$$

6 step solution

Problem 67

The formula specifles the position of a point \(P\) that is moving harmonically on a vertical axis, where \(t\) is in seconds and \(d\) is in centimeters. Determine the amplitude, period, and frequency, and describe the motion of the point during one complete oscillation (starting at \(t=0\) ). $$d=10 \sin 6 \pi t$$

4 step solution

Problem 67

Graph the equation on the Interval \([-20,20]\), and estimate the hortzontal asymptote. \(y=x^{2} \sin ^{2}\left(\frac{2}{x}\right)\)

5 step solution

Problem 67

Practice sketching the graph of the sine function, taking different units of length on the horizontal and vertical axes. Practice sketching graphs of the cosine and tangent functions in the same manner. Continue this practice until you reach the stage at which, if you were awakened from a sound sleep in the middle of the night and asked to sketch one of these graphs, you could do so in less than thirty seconds.

6 step solution

Problem 67

Graph the function \(f\) in the viewing rectangle \([-2 \pi, 2 \pi, \pi / 2]\) by \([-4,4] .\) Use the graph of \(f\) to predict the graph of \(g .\) Verify your prediction by graphing \(g\) in the same vlewing rectangle. $$f(x)=\tan 0.5 x ; \quad g(x)=\tan \left[0.5\left(x+\frac{\pi}{2}\right)\right]$$

4 step solution

Problem 67

Verify the identity by transforming the lefthand side into the right-hand side. $$\sec ^{2} 3 \theta \csc ^{2} 3 \theta=\sec ^{2} 3 \theta+\csc ^{2} 3 \theta$$

3 step solution

Problem 68

The formula specifles the position of a point \(P\) that is moving harmonically on a vertical axis, where \(t\) is in seconds and \(d\) is in centimeters. Determine the amplitude, period, and frequency, and describe the motion of the point during one complete oscillation (starting at \(t=0\) ). $$d=\frac{1}{3} \cos \frac{\pi}{4} t$$

5 step solution

Problem 68

Graph the equation on the Interval \([-20,20]\), and estimate the hortzontal asymptote. \(y=\frac{1-\cos ^{2}(2 / x)}{\sin (1 / x)}\)

4 step solution

Problem 68

Graph the function \(f\) in the viewing rectangle \([-2 \pi, 2 \pi, \pi / 2]\) by \([-4,4] .\) Use the graph of \(f\) to predict the graph of \(g .\) Verify your prediction by graphing \(g\) in the same vlewing rectangle. $$f(x)=0.5 \csc 0.5 x, g(x)=0.5 \csc 0.5 x-2$$

5 step solution

Problem 68

Verify the identity by transforming the lefthand side into the right-hand side. $$\frac{1+\cos ^{2} 3 \theta}{\sin ^{2} 3 \theta}=2 \csc ^{2} 3 \theta-1$$

5 step solution

Problem 69

The formula specifles the position of a point \(P\) that is moving harmonically on a vertical axis, where \(t\) is in seconds and \(d\) is in centimeters. Determine the amplitude, period, and frequency, and describe the motion of the point during one complete oscillation (starting at \(t=0\) ). $$d=4 \cos \frac{3 \pi}{2} t$$

4 step solution

Problem 69

Graph the function \(f\) in the viewing rectangle \([-2 \pi, 2 \pi, \pi / 2]\) by \([-4,4] .\) Use the graph of \(f\) to predict the graph of \(g .\) Verify your prediction by graphing \(g\) in the same vlewing rectangle. $$f(x)=0.5 \sec 0.5 x, \quad g(x)=0.5 \sec \left[0.5\left(x-\frac{\pi}{2}\right)\right]-1$$

6 step solution

Problem 69

Verify the identity by transforming the lefthand side into the right-hand side. $$\log \csc \theta=-\log \sin \theta$$

6 step solution

Problem 70

The formula specifles the position of a point \(P\) that is moving harmonically on a vertical axis, where \(t\) is in seconds and \(d\) is in centimeters. Determine the amplitude, period, and frequency, and describe the motion of the point during one complete oscillation (starting at \(t=0\) ). $$d=6 \sin \frac{2 \pi}{3} t$$

5 step solution

Problem 70

Use a graph to solve the Inequality on the interval \([-\pi, \pi]\) \(\frac{1}{4} \tan \left(\frac{1}{3} x^{2}\right)<\frac{1}{2} \cos 2 x+\frac{1}{5} x^{2}\)

6 step solution

Problem 70

Graph the function \(f\) in the viewing rectangle \([-2 \pi, 2 \pi, \pi / 2]\) by \([-4,4] .\) Use the graph of \(f\) to predict the graph of \(g .\) Verify your prediction by graphing \(g\) in the same vlewing rectangle. $$f(x)=\tan x-1 ; \quad g(x)=-\tan x+1$$

6 step solution

Problem 70

Verify the identity by transforming the lefthand side into the right-hand side. $$\log \tan \theta=\log \sin \theta-\log \cos \theta$$

5 step solution

Problem 71

A point \(P\) in simple harmonic motion has a period of 3 seconds and an amplitude of 5 centimeters. Express the motion of \(P\) by means of an equation of the form \(d=a \cos \omega t\)

5 step solution

Problem 71

Graph the function \(f\) in the viewing rectangle \([-2 \pi, 2 \pi, \pi / 2]\) by \([-4,4] .\) Use the graph of \(f\) to predict the graph of \(g .\) Verify your prediction by graphing \(g\) in the same vlewing rectangle. $$f(x)=3 \cos 2 x ; \quad g(x)=|3 \cos 2 x|-1$$

6 step solution

Problem 71

Find the exact values of the six trigonometric functions of \(\boldsymbol{\theta}\) if \(\boldsymbol{\theta}\) is in standard position and \(P\) is on the terminal side. $$P(4,-3)$$

8 step solution

Problem 72

Find the exact values of the six trigonometric functions of \(\boldsymbol{\theta}\) if \(\boldsymbol{\theta}\) is in standard position and \(P\) is on the terminal side. $$P(-8,-15)$$

7 step solution

Problem 73

On March \(17,1981,\) in Tucson, Arizona, the temperature in degrees Fahrenheit could be described by the equation $$T(t)=-12 \cos \left(\frac{\pi}{12} t\right)+60$$ while the relative humidity in percent could be expressed by $$H(t)=20 \cos \left(\frac{\pi}{12} t\right)+60$$ where \(t\) is in hours and \(t=0\) corresponds to 6 A.M. (a) Construct a table that lists the temperature and relative humidity every three hours, beginning at midnight. (b) Determine the times when the maximums and minimums occurred for \(T\) and \(H\) (c) Discuss the relationship between the temperature and relative humidity on this day.

4 step solution

Problem 73

Identify the damping factor \(f(x)\) for the damped wave. Sketch graphs of \(y=\pm f(x)\) and the equation on the same coordinate plane for \(-2 \pi \leq x \leq 2 \pi\) $$y=e^{-x^{4}} \sin 4 x$$

3 step solution

Problem 73

Find the exact values of the six trigonometric functions of \(\boldsymbol{\theta}\) if \(\boldsymbol{\theta}\) is in standard position and \(P\) is on the terminal side. $$P(-2,-5)$$

4 step solution

Problem 74

Identify the damping factor \(f(x)\) for the damped wave. Sketch graphs of \(y=\pm f(x)\) and the equation on the same coordinate plane for \(-2 \pi \leq x \leq 2 \pi\) $$y=3^{-x / 3} \cos 2 x$$

5 step solution

Problem 74

Find the exact values of the six trigonometric functions of \(\boldsymbol{\theta}\) if \(\boldsymbol{\theta}\) is in standard position and \(P\) is on the terminal side. $$P(-1,2)$$

8 step solution

Problem 75

Graph the equation, and estimate the values of \(x\) in the specified interval that correspond to the given value of \(y\) $$y=\sin \left(x^{2}\right), \quad[-\pi, \pi] ; \quad y=0.5$$

5 step solution

Problem 75

Graph the function \(f\) on \([-\pi, \pi],\) and estimate the high and low points. $$f(x)=\cos 2 x+2 \sin 4 x-\sin x$$

4 step solution

Problem 75

Find the exact values of the six trigonometric functions of \(\boldsymbol{\theta}\) if \(\boldsymbol{\theta}\) is in standard position and the terminal side of \(\boldsymbol{\theta}\) is in the specified quadrant and satisfles the given condition. II; on the line \(y=-4 x\)

4 step solution

Problem 76

Graph the equation, and estimate the values of \(x\) in the specified interval that correspond to the given value of \(y\) $$y=\tan (\sqrt{x}), \quad[0,25] ; \quad y=5$$

5 step solution

Problem 76

Graph the function \(f\) on \([-\pi, \pi],\) and estimate the high and low points. $$f(x)=\tan \frac{1}{4} x-2 \sin 2 x$$

5 step solution

Problem 76

Find the exact values of the six trigonometric functions of \(\boldsymbol{\theta}\) if \(\boldsymbol{\theta}\) is in standard position and the terminal side of \(\boldsymbol{\theta}\) is in the specified quadrant and satisfles the given condition. IV; on the line \(3 y+5 x=0\)

6 step solution

Problem 77

Graph \(f\) on the Interval \([-2 \pi, 2 \pi],\) and estimate the coordinates of the high and low points. $$f(x)=x \sin x$$

7 step solution

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