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