homework homework assignment #8 read section 5.8 page 355, exercises: 1 – 69(eoo) quiz next time...

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Homework Homework Assignment #8 Read Section 5.8 Page 355, Exercises: 1 – 69(EOO) Quiz next time Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

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Homework

Homework Assignment #8 Read Section 5.8 Page 355, Exercises: 1 – 69(EOO) Quiz next time

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

Example, Page 355Evaluate the definite integral.

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

2

1

11. dx

x

22

1 1

2

1

1ln ln 2 ln1 ln 2

1ln 2

dx xx

dxx

Example, Page 355Evaluate the definite integral.

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

2

15. e

e dtt

2 2

2

2

1ln

ln ln 1 2 1

11

ee

e e

e

e

dt tt

e e

dtt

x

y

Example, Page 355Evaluate the definite integral.

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

23

2 2

19.

1dx

x x

2 213 3

2 22

23

2 2

1sec

6 3 61

1

61

dx xx x

dxx x

Example, Page 355Evaluate the definite integral.

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

2

0 2

113.

4dx

x

2

2 2 2 10 0 0 22

2 0

1 1

2

0 2

111 1 1 14 tan

14 4 4 214 441 1

tan 1 tan 0 04 4 4 16

1

4 16

xdx dx dx

xx x

dxx

Example, Page 355Evaluate the indefinite integral.

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

217.

25 4

dt

t

1

2 22

1

2

11 1 25 sin

1 5 5 5425 4 125 4 255

1 2sin

5 525 4

dtdt dt tC

t tt

dt tC

t

Example, Page 355Evaluate the indefinite integral.

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

2

121.

1

x dx

x

2

2 2 2

21 1

2 2

1 2

2

11 , 2 ,

21 1 1

1 1 1sin sin

12 21 1 2

1sin 1

1

x dx xdx dx du duu x x xdx

dxx x x

xdx dx du xx C x C

ux x

x dxx x C

x

Example, Page 355Evaluate the indefinite integral.

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

1

2

tan25.

1

xdx

x

12 2

1 221

2

121

2

1tan , ,

1 1

tantan

1 2

tantan

1

du dxu x du

dx x x

xdx uudu C x C

x

xdxx C

x

Example, Page 355Evaluate the definite integral.

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

4log 3

029. 4x dx

4 4

4

4

log 3 log 3 0log 3

0

0

log 3

0

4 4 4 3 1 24

ln 4 ln 4 ln 4 ln 4 ln 4 ln 4

24

ln 4

xx

x

dx

dx

Example, Page 355Evaluate the integral using methods covered so far.

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

33. 2xe dx

2 2 2

2 2

x x x

x x

e dx e dx dx e x C

e dx e x C

Example, Page 355Evaluate the integral using methods covered so far.

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

437. 1xe dx

4 4

4 4

4 4

1 4 , 4,4

1 1 1

4 4 4

11

4

x x

x u u x

x x

du due dx e dx dx u x dx

dx

e dx dx e du x C e x C e x C

e dx e x C

Example, Page 355Evaluate the integral using methods covered so far.

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

241.

1 16

dx

x

1 1

2 2

1

2

4 , 4,4

1 1 1sin sin 4

4 4 41 16 1

1sin 4

41 16

du duu x dx

dxdx du

u C x Cx u

dxx C

x

Example, Page 355Evaluate the integral using methods covered so far.

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

1045. 7 xe dx

10

10

10 , 1010

17 7 7

10 10

7 10 710

ux u

xx

du duu x dx

dx

ee dx dx e du x C

ee dx x C

Example, Page 355Evaluate the integral using methods covered so far.

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

2449. xxe dx

2 2

2 2

2

4 4

4 4

4 , 8 ,8

1 1 1

8 8 8

1

8

x u u x

x x

du duu x x xdx

dx

xe dx e du e C e C

xe dx e C

Example, Page 355Evaluate the integral using methods covered so far.

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

53. 2 4

dx

x

2 4, 2,2

1 1 1ln ln 2 4

2 4 2 2 2

1ln 2 4

2 4 2

du duu x dx

dxdx du

u C x Cx u

dxx C

x

Example, Page 355Evaluate the integral using methods covered so far.

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

57. tan 4 1x dx

4 1, 4,4

cos1 1 sin

tan 4 1 tan4 4 cos sin

1 sin 1 1 1ln ln cos

4 cos 4 4 41

ln cos 4 14

1tan 4 1 ln cos 4 1

4

du duu x dx

dxv u

ux dx udu du dv

u udu

u dvdu v C u C

u v

x C

x dx x C

Example, Page 355Evaluate the indefinite integral.

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

4ln 561.

xdx

x

22

2

4ln 5 4ln 5 1ln , ,

4 ln 54 5 4 ln 2 ln ln

2

4ln 52 ln ln

x x du dxdx dx dx u x du

x x x dx x x

x dx udx udu x C x x C

x x

xdx x x C

x

Example, Page 355Evaluate the indefinite integral.

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

ln ln65.

ln

xdx

x x

22

2

ln ln 1ln ln , ,

ln ln lnln ln 1

ln lnln 2 2

ln ln 1ln ln

ln 2

x du dxdx u x du

x x dx x x x xx u

dx udu C x Cx x

xdx x C

x x

Example, Page 355Evaluate the indefinite integral.

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

sin69. cos 3 xx dx

sin

sinsin

sinsin

cos 3 sin , cos , cos

3 3cos 3 3

ln 3 ln 3

3cos 3

ln 3

x

u xx u

xx

dux dx u x x du xdx

dx

x dx du C C

x dx C

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

Chapter 5: The IntegralSection 5.8: Exponential Growth and Decay

Jon Rogawski

Calculus, ETFirst Edition

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

There are many examples in biology, physics, and economics where“populations “ grow or decay at exponential rates. The general formula describing this growth or decay is:

If k > 0, then the population is growing and if k < 0, the population is decaying.

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

The e. coli bacteria shown in Figure 1 multiply exponentially. That is why, within hours of ingesting contaminated food or drink, a person becomes severely ill from this bacteria.

As can be extrapolated from the graph in Figure 2, in less than 24hours, an initial population of 1,000 bacteria would have grown to over 1,600,000, more than enough to affect the healthiest person.

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

If a quantity is changing in proportion to the amount currently present, then it is increasing/decreasing exponentially

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

The rate a which penicillin leaves the bloodstream is proportional to the amount present. If an initial amount of 450 mg is administered and 50 mg remains after seven hours, what is the decay constant? At what time after the injection, did 200 mg remain?

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

A frequently asked question is: “When will this process produce twice the original amount?” This question can be answered bysolving 2 = 1 ekt for t.

Example, Page 3662. A quantity P obeys exponential growth law P = e5t (t in years).

(a) At what time t is P = 10?

(b) At what time t is P = 20?

(c) What is the doubling time for P?

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

Figure 4 shows a graph of the number of bachelor’s degrees awardedin physics each year from 1955 to about 1978. The figure is markedto emphasize the doubling that took place about every seven years.

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

If the number of microscopic plants shown in Figure 5 doubles every30 hours, what is the k value we should use?

Rogawski CalculusCopyright © 2008 W. H. Freeman and Company

In the case of exponential decay, the half-life of the substance is calculated by using:

Archeologists use the half-life of carbon-14 to date organic materials.The process was developed following World War II.