Chapter 1

Calculus for Biology and Medicine · 307 exercises

Problem 19

Sketch the graph of each function. Do not use a graphing calculator. (Assume the largest possible domain.) $$ y=2 \sin (x+\pi / 4) $$

6 step solution

Problem 19

Suppose that \(f(x)=x^{2}, x \geq 0\), and \(g(x)=\sqrt{x}, x \geq 0\). Typically, \(f \circ g \neq g \circ f\), but this is an example in which the order of composition does not matter. Show that \(f \circ g=g \circ f\).

4 step solution

Problem 19

Determine the equation of the line that satisfies the stated requirements. Put the equation in standard form. The line with slope 3 and \(y\) -intercept \((0,2)\)

4 step solution

Problem 20

Sketch the graph of each function. Do not use a graphing calculator. (Assume the largest possible domain.) $$ y=0.2 \cos (-x) $$

5 step solution

Problem 20

Suppose that \(f(x)=x^{4}, x \geq 0\). Find \(g(x)\) so that \(f \circ g=g \circ f\).

5 step solution

Problem 20

Determine the equation of the line that satisfies the stated requirements. Put the equation in standard form. The line with slope \(-1\) and \(y\) -intercept \((0,-3)\)

4 step solution

Problem 21

Sketch the graph of each function. Do not use a graphing calculator. (Assume the largest possible domain.) $$ y=-\sin (\pi x / 2) $$

6 step solution

Problem 21

Use a graphing calculator to graph \(f(x)=x^{2}, x \geq 0\), and \(g(x)=x^{4}, x \geq 0\), together. For which values of \(x\) is \(f(x)>g(x)\) and for which is \(f(x)

5 step solution

Problem 21

Determine the equation of the line that satisfies the stated requirements. Put the equation in standard form. The line with slope \(1 / 2\) and \(y\) -intercept \((0,2)\)

4 step solution

Problem 22

Sketch the graph of each function. Do not use a graphing calculator. (Assume the largest possible domain.) $$ y=-2 \cos (\pi x / 4) $$

7 step solution

Problem 22

Use a graphing calculator to graph \(f(x)=x^{3}, x \geq 0\), and \(g(x)=x^{5}, x \geq 0\), together. When is \(f(x)>g(x)\), and when is \(f(x)

6 step solution

Problem 22

Determine the equation of the line that satisfies the stated requirements. Put the equation in standard form. The line with slope \(-1 / 3\) and \(y\) -intercept \((0,-1)\)

4 step solution

Problem 23

Explain how the following functions can be obtained from \(y=x^{2}\) by basic transformations: (a) \(y=x^{2}-2\) (b) \(y=(x-1)^{2}+1\) (c) \(y=-2(x+2)^{2}\)

4 step solution

Problem 23

Graph \(y=x^{n}, x \geq 0\), for \(n=1,2,3\), and 4 in one coordinate system. Where do the curves intersect?

3 step solution

Problem 23

Determine the equation of the line that satisfies the stated requirements. Put the equation in standard form. The line with slope \(-2\) and \(x\) -intercept \((1,0)\)

4 step solution

Problem 24

Explain how the following functions can be obtained from \(y=x^{3}\) by basic transformations: (a) \(y=x^{3}+1\) (b) \(y=(x+1)^{3}-1\) (c) \(y=-3(x-2)^{3}\)

4 step solution

Problem 24

(a) Graph \(f(x)=x, x \geq 0\), and \(g(x)=x^{2}, x \geq 0\), together, in one coordinate system. (b) For which values of \(x\) is \(f(x) \geq g(x)\), and for which values of \(x\) is \(f(x)

5 step solution

Problem 24

Determine the equation of the line that satisfies the stated requirements. Put the equation in standard form. The line with slope 1 and \(x\) -intercept \((-2,0)\)

4 step solution

Problem 25

Explain how the following functions can be obtained from \(y=1 / x\) by basic transformations: (a) \(y=1-\frac{1}{x}\) (b) \(y=-\frac{1}{x-1}\) (c) \(y=\frac{x}{x+1}\)

4 step solution

Problem 25

(a) Graph \(f(x)=x^{2}\) and \(g(x)=x^{3}\) for \(x \geq 0\), together, in one coordinate system. (b) Show algebraically that $$ x^{2} \geq x^{3} $$ for \(0 \leq x \leq 1\) (c) Show algebraically that $$ x^{2} \leq x^{3} $$ for \(x \geq 1\).

4 step solution

Problem 25

Determine the equation of the line that satisfies the stated requirements. Put the equation in standard form. The line with slope \(-1 / 4\) and \(x\) -intercept \((3,0)\)

5 step solution

Problem 26

Explain how the following functions can be obtained from \(y=1 / x^{2}\) by basic transformations: (a) \(y=\frac{1}{x^{2}}+1\) (b) \(y=-\frac{1}{(x+1)^{2}}\) (c) \(y=-\frac{1}{x^{2}}-2\)

4 step solution

Problem 26

Show algebraically that if \(n \geq m\), $$ x^{n} \leq x^{m} \quad \text { for } 0 \leq x \leq 1 $$ and $$ x^{n} \geq x^{m} \quad \text { for } x \geq 1 $$

3 step solution

Problem 26

Determine the equation of the line that satisfies the stated requirements. Put the equation in standard form. The line with slope \(1 / 5\) and \(x\) -intercept \((-1 / 2,0)\)

4 step solution

Problem 27

Explain how the following functions can be obtained from \(y=e^{x}\) by basic transformations: (a) \(y=2 e^{x}-1\) (b) \(y=-e^{-x}\) (c) \(y=e^{x-2}+1\)

3 step solution

Problem 27

(a) Show that \(y=x^{2}, x \in \mathbf{R}\), is an even function. (b) Show that \(y=x^{3}, x \in \mathbf{R}\), is an odd function.

4 step solution

Problem 27

Determine the equation of the line that satisfies the stated requirements. Put the equation in standard form. The line passing through \((2,-3)\) and parallel to $$ x+2 y-4=0 $$

5 step solution

Problem 28

Explain how the following functions can be obtained from \(y=e^{x}\) by basic transformations: (a) \(y=e^{-x}-1\) (b) \(y=-e^{x}+1\) (c) \(y=-e^{x-3}-2\)

4 step solution

Problem 28

Show that (a) \(y=x^{n}, x \in \mathbf{R}\), is an even function when \(n\) is an even integer. (b) \(y=x^{n}, x \in \mathbf{R}\), is an odd function when \(n\) is an odd integer.

3 step solution

Problem 28

Determine the equation of the line that satisfies the stated requirements. Put the equation in standard form. The line passing through (1,2) and parallel to $$ x-3 y-6=0 $$

5 step solution

Problem 29

Explain how the following functions can be obtained from \(y=\ln x\) by basic transformations: (a) \(y=\ln (x-1)\) (b) \(y=-\ln x+1\) (c) \(y=\ln (x+3)-1\)

4 step solution

Problem 29

Determine the equation of the line that satisfies the stated requirements. Put the equation in standard form. The line passing through \((-1,-1)\) and parallel to the line passing through \((0,1)\) and \((3,0)\)

4 step solution

Problem 30

Explain how the following functions can be obtained from \(y=\ln x\) by basic transformations: (a) \(y=\ln (1-x)\) (b) \(y=\ln (2+x)-1\) (c) \(y=-\ln (2-x)+1\)

4 step solution

Problem 30

An autocatalytic reaction uses its resulting product for the formation of a new product, as in the reaction $$ \mathrm{A}+\mathrm{X} \rightarrow \mathrm{X} $$ If we assume that this reaction occurs in a closed vessel, then the reaction rate is given by $$ R(x)=k x(a-x) $$ for \(0 \leq x \leq a\), where \(a\) is the initial concentration of \(A\) and \(x\) is the concentration of \(X\). (a) Show that \(R(x)\) is a polynomial and determine its degree. (b) Graph \(R(x)\) for \(k=2\) and \(a=6\). Find the value of \(x\) at which the reaction rate is maximal.

5 step solution

Problem 30

Determine the equation of the line that satisfies the stated requirements. Put the equation in standard form. The line passing through \((2,-3)\) and parallel to the line passing through \((0,-1)\) and \((2,1)\)

4 step solution

Problem 31

Explain how the following functions can be obtained from \(y=\sin x\) by basic transformations: (a) \(y=1-\sin x\) (b) \(y=\sin \left(x-\frac{\pi}{4}\right)\) (c) \(y=-\sin \left(x+\frac{\pi}{3}\right)\)

4 step solution

Problem 31

Suppose that a beetle walks up a tree along a straight line at a constant speed of 1 meter per hour. What distance will the beetle have covered after 1 hour, 2 hours, and 3 hours? Write an equation that expresses the distance (in meters) as a function of the time (in hours), and show that this function is a polynomial of degree \(1 .\)

6 step solution

Problem 31

Determine the equation of the line that satisfies the stated requirements. Put the equation in standard form. The line passing through \((1,4)\) and perpendicular to $$ 2 y-5 x+7=0 $$

6 step solution

Problem 32

Explain how the following functions can be obtained from \(y=\cos x\) by basic transformations: (a) \(y=1+2 \cos x\) (b) \(y=-\cos \left(x+\frac{\pi}{4}\right)\) (c) \(y=-\cos \left(\frac{\pi}{2}-x\right)\)

3 step solution

Problem 32

Suppose that a fungal disease originates in the middle of an orchard, initially affecting only one tree. The disease spreads out radially at a constant speed of 10 feet per day. What area will be affected after 2 days, 4 days, and 8 days? Write an equation that expresses the affected area as a function of time, measured in days, and show that this function is a polynomial of degree \(2 .\)

5 step solution

Problem 32

Determine the equation of the line that satisfies the stated requirements. Put the equation in standard form. The line passing through \((-1,-1)\) and perpendicular to $$ x-y+3=0 $$

5 step solution

Problem 33

Find the following numbers on a number line that is on a logarithmic scale (base 10\(): 0.0002,0.02,1,5,50,100,1000,8000\), and 20000 .

4 step solution

Problem 33

In Problems 33-36, for each function, find the largest possible domain and determine the range. $$ f(x)=\frac{1}{1-x} $$

4 step solution

Problem 33

Determine the equation of the line that satisfies the stated requirements. Put the equation in standard form. The line passing through \((5,-1)\) and perpendicular to the line passing through \((-2,1)\) and \((1,-2)\)

4 step solution

Problem 34

Find the following numbers on a number line that is on a logarithmic scale (base 10\(): 0.03,0.7,1,2,5,10,17,100,150\), and \(2000 .\)

4 step solution

Problem 34

For each function, find the largest possible domain and determine the range. $$ f(x)=\frac{2 x}{(x-2)(x+3)} $$

3 step solution

Problem 34

Determine the equation of the line that satisfies the stated requirements. Put the equation in standard form. The line passing through \((4,-1)\) and perpendicular to the line passing through \((-2,0)\) and \((1,1)\)

5 step solution

Problem 35

Find the following numbers on a number line that is on a logarithmic scale (base 10\(): 10^{2}, 10^{-3}, 10^{-4}, 10^{-7}\), and \(10^{-10}\). (b) Can you find 0 on a number line that is on a logarithmic scale? (c) Can you find negative numbers on a number line that is on a logarithmic scale?

8 step solution

Problem 35

For each function, find the largest possible domain and determine the range. $$ f(x)=\frac{x-2}{x^{2}-9} $$

6 step solution

Problem 35

Determine the equation of the line that satisfies the stated requirements. Put the equation in standard form. The line passing through \((4,2)\) and parallel to the horizontal line passing through \((1,-2)\)

3 step solution

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