Chapter 6

Calculus for Biology and Medicine · 262 exercises

Problem 18

Write each sum in sigma notation. $$ \frac{3}{5}+\frac{4}{6}+\frac{5}{7}+\frac{6}{8}+\frac{7}{9} $$

4 step solution

Problem 19

Use Leibniz's rule to find \(\frac{d y}{d x}\). $$ y=\int_{4}^{x^{2}+1} \sqrt{t} d t, x>0 $$

4 step solution

Problem 19

A particle moves along the \(x\) -axis with velocity $$ v(t)=-(t-2)^{2}+1 $$ for \(0 \leq t \leq 5\). Assume that the particle is at the origin at time 0 . (a) Graph \(v(t)\) as a function of \(t\). (b) Use the graph of \(v(t)\) to determine when the particle moves to the left and when it moves to the right. (c) Find the location \(s(t)\) of the particle at time \(t\) for \(0 \leq t \leq 5\). Give a geometric interpretation of \(s(t)\) in terms of the graph of \(v(t)\) (d) Graph \(s(t)\) and find the leftmost and rightmost positions of the particle.

5 step solution

Problem 20

Use Leibniz's rule to find \(\frac{d y}{d x}\). $$ y=\int_{2}^{x^{2}-2} \sqrt{3+u} d u, x>0 $$

6 step solution

Problem 20

Recall that the acceleration \(a(t)\) of a particle moving along a straight line is the instantaneous rate of change of the velocity \(v(t) ;\) that is, $$ a(t)=\frac{d}{d t} v(t) $$ Assume that \(a(t)=32 \mathrm{ft} / \mathrm{s}^{2} .\) Express the cumulative change in velocity during the interval \([0, t]\) as a definite integral, and compute the integral.

3 step solution

Problem 20

Write each sum in sigma notation. $$ \frac{1}{1}+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\cdots+\frac{1}{2^{n}} $$

3 step solution

Problem 21

Use Leibniz's rule to find \(\frac{d y}{d x}\). $$ y=\int_{0}^{3 x}\left(1+e^{t}\right) d t $$

4 step solution

Problem 21

If \(\frac{d l}{d t}\) represents the growth rate of an organism at time \(t\) (measured in months), explain what $$ \int_{2}^{7} \frac{d l}{d t} d t $$ represents.

3 step solution

Problem 21

Write each sum in sigma notation. $$ 1+q+q^{2}+q^{3}+q^{4}+\cdots+q^{n-1} $$

4 step solution

Problem 22

Use Leibniz's rule to find \(\frac{d y}{d x}\). $$ y=\int_{0}^{2 x^{2}-1}\left(e^{-2 t}+e^{2 t}\right) d t $$

5 step solution

Problem 22

If \(\frac{d w}{d x}\) represents the rate of change of the weight of an organism of age \(x\), explain what $$ \int_{3}^{5} \frac{d w}{d x} d x $$ means.

3 step solution

Problem 22

Write each sum in sigma notation. $$ 1-a+a^{2}-a^{3}+a^{4}-a^{5}+\cdots+(-1)^{n} a^{n} $$

3 step solution

Problem 23

Use Leibniz's rule to find \(\frac{d y}{d x}\). $$ y=\int_{1}^{3 x^{2}+x}\left(1+t e^{t}\right) d t $$

5 step solution

Problem 23

If \(\frac{d B}{d t}\) represents the rate of change of biomass at time \(t\), explain what $$ \int_{1}^{6} \frac{d B}{d t} d t $$ means.

4 step solution

Problem 23

Use the algebraic rules for sums to evaluate each sum. Recall that $$\sum_{k=1}^{n} k=\frac{n(n+1)}{2}$$ and $$\sum_{k=1}^{n} k^{2}=\frac{n(n+1)(2 n+1)}{6}$$ $$ \sum_{k=1}^{15}(2 k+3) $$

5 step solution

Problem 24

Use Leibniz's rule to find \(\frac{d y}{d x}\). $$ y=\int_{2}^{\ln x} e^{-t} d t, x>0 $$

4 step solution

Problem 24

Let \(N(t)\) denote the size of a population at time \(t\), and assume that $$ \frac{d N}{d t}=f(t) $$ Express the cumulative change of the population size in the interval \([0,3]\) as an integral.

4 step solution

Problem 24

Use the algebraic rules for sums to evaluate each sum. Recall that $$\sum_{k=1}^{n} k=\frac{n(n+1)}{2}$$ and $$\sum_{k=1}^{n} k^{2}=\frac{n(n+1)(2 n+1)}{6}$$ $$ \sum_{k=1}^{5}\left(4-k^{2}\right) $$

4 step solution

Problem 25

Use Leibniz's rule to find \(\frac{d y}{d x}\). $$ y=\int_{x}^{3}(1+t) d t $$

4 step solution

Problem 25

Let \(f(x)=x^{2}-2\). Compute the average value of \(f(x)\) over the interval \([0,2]\).

5 step solution

Problem 25

Use the algebraic rules for sums to evaluate each sum. Recall that $$\sum_{k=1}^{n} k=\frac{n(n+1)}{2}$$ and $$\sum_{k=1}^{n} k^{2}=\frac{n(n+1)(2 n+1)}{6}$$ $$ \sum_{k=0}^{6} k(k+1) $$

7 step solution

Problem 26

Use Leibniz's rule to find \(\frac{d y}{d x}\). $$ y=\int_{x}^{5}\left(1+e^{t}\right) d t $$

4 step solution

Problem 26

Let \(g(t)=\sin (\pi t) .\) Compute the average value of \(g(t)\) over the interval \([-1,1]\).

6 step solution

Problem 26

Use the algebraic rules for sums to evaluate each sum. Recall that $$\sum_{k=1}^{n} k=\frac{n(n+1)}{2}$$ and $$\sum_{k=1}^{n} k^{2}=\frac{n(n+1)(2 n+1)}{6}$$ $$ \sum_{k=1}^{n} 4 k $$

3 step solution

Problem 27

Use Leibniz's rule to find \(\frac{d y}{d x}\). $$ y=\int_{2 x}^{3}(1+\sin t) d t $$

6 step solution

Problem 27

Suppose that the temperature \(T\) (measured in degrees Fahrenheit) in a growing chamber varies over a 24 -hour period according to $$ T(t)=68+\sin \left(\frac{\pi}{12} t\right) $$ for \(0 \leq t \leq 24\). (a) Graph the temperature \(T\) as a function of time \(t\). (b) Find the average temperature and explain your answer graphically.

5 step solution

Problem 27

Use the algebraic rules for sums to evaluate each sum. Recall that $$\sum_{k=1}^{n} k=\frac{n(n+1)}{2}$$ and $$\sum_{k=1}^{n} k^{2}=\frac{n(n+1)(2 n+1)}{6}$$ $$ \sum_{k=1}^{n} 4(k-1)^{2} $$

7 step solution

Problem 28

Use Leibniz's rule to find \(\frac{d y}{d x}\). $$ y=\int_{2 x^{2}}^{6}(1+\tan t) d t $$

5 step solution

Problem 28

Suppose that the concentration (measured in \(\mathrm{gm}^{-3}\) ) of nitrogen in the soil along a transect in moist tundra yields data points that follow a straight line with equation $$ y=673.8-34.7 x $$ for \(0 \leq x \leq 10\), where \(x\) is the distance to the beginning of the transect. What is the average concentration of nitrogen in the soil along this transect?

7 step solution

Problem 28

Use the algebraic rules for sums to evaluate each sum. Recall that $$\sum_{k=1}^{n} k=\frac{n(n+1)}{2}$$ and $$\sum_{k=1}^{n} k^{2}=\frac{n(n+1)(2 n+1)}{6}$$ $$ \sum_{k=1}^{n}(k+2)(k-2) $$

4 step solution

Problem 29

Use Leibniz's rule to find \(\frac{d y}{d x}\). $$ y=\int_{x}^{5} \frac{1}{u^{2}} d u, x>0 $$

2 step solution

Problem 29

Let \(f(x)=\tan x\). Give a geometric argument to explain why the average value of \(f(x)\) over \([-1,1]\) is equal to 0 .

4 step solution

Problem 29

Use the algebraic rules for sums to evaluate each sum. Recall that $$\sum_{k=1}^{n} k=\frac{n(n+1)}{2}$$ and $$\sum_{k=1}^{n} k^{2}=\frac{n(n+1)(2 n+1)}{6}$$ $$ \sum_{k=1}^{10}(-1)^{k} $$

4 step solution

Problem 30

Use Leibniz's rule to find \(\frac{d y}{d x}\). $$ y=\int_{x^{2}}^{3} \frac{1}{1+t} d t, x>0 $$

4 step solution

Problem 30

Suppose that you drive from St. Paul to Duluth and you average \(50 \mathrm{mph}\). Explain why there must be a time during your trip at which your speed is exactly \(50 \mathrm{mph}\).

4 step solution

Problem 30

Use the algebraic rules for sums to evaluate each sum. Recall that $$\sum_{k=1}^{n} k=\frac{n(n+1)}{2}$$ and $$\sum_{k=1}^{n} k^{2}=\frac{n(n+1)(2 n+1)}{6}$$ $$ \sum_{k=0}^{10}(-1)^{k} $$

4 step solution

Problem 31

Use Leibniz's rule to find \(\frac{d y}{d x}\). $$ y=\int_{x^{2}}^{1} \sec t d t,-1

5 step solution

Problem 31

Let \(f(x)=2 x, 0 \leq x \leq 2\). Use a geometric argument to find the average value of \(f\) over the interval \([0,2]\), and find \(x\) such that \(f(x)\) is equal to this average value.

5 step solution

Problem 32

Use Leibniz's rule to find \(\frac{d y}{d x}\). $$ y=\int_{2+x^{2}}^{2} \cot t d t $$

4 step solution

Problem 32

A particle moves along the \(x\) -axis with velocity $$ v(t)=-(t-3)^{2}+5 $$ for \(0 \leq t \leq 6\). (a) Graph \(v(t)\) as a function of \(t\) for \(0 \leq t \leq 6\). (b) Find the average velocity of this particle during the interval \([0,6] .\) (c) Find a time \(t^{*} \in[0,6]\) such that the velocity at time \(t^{*}\) is equal to the average velocity during the interval \([0,6] .\) Is it clear that such a point exists? Is there more than one such point in this case? Use your graph in (a) to explain how you would find \(t^{*}\) graphically.

4 step solution

Problem 32

Approximate $$\int_{-1}^{1}\left(1-x^{2}\right) d x$$ using five equal subintervals and left endpoints.

6 step solution

Problem 33

Use Leibniz's rule to find \(\frac{d y}{d x}\). $$ y=\int_{x}^{2 x}\left(1+t^{2}\right) d t $$

7 step solution

Problem 33

Find the volume of a right circular cone with base radius \(r\) and height \(h\).

3 step solution

Problem 33

Approximate $$\int_{-1}^{1}\left(1-x^{2}\right) d x$$ using five equal subintervals and midpoints.

5 step solution

Problem 34

Use Leibniz's rule to find \(\frac{d y}{d x}\). $$ y=\int_{-x}^{x} \tan u d u, 0

4 step solution

Problem 34

Find the volume of a pyramid with square base of side length \(a\) and height \(\bar{h}\).

4 step solution

Problem 34

Approximate $$\int_{-1}^{1}\left(2+x^{2}\right) d x$$ using five equal subintervals and right endpoints.

4 step solution

Problem 35

Use Leibniz's rule to find \(\frac{d y}{d x}\). $$ y=\int_{x^{2}}^{x^{3}} \ln (t-3) d t, x>0 $$

7 step solution

Problem 35

Approximate $$\int_{-2}^{2}\left(2+x^{2}\right) d x$$ using four equal subintervals and left endpoints.

5 step solution

Problem 36

Use Leibniz's rule to find \(\frac{d y}{d x}\). $$ y=\int_{x^{3}}^{x^{4}} \ln \left(1+t^{2}\right) d t, x>0 $$

4 step solution

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