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  • Use a table of integrals to solve integration problems.
  • Use a computer algebra system (CAS) to solve integration problems.

In addition to the techniques of integration we have already seen, several other tools are widely available to assist with the process of integration. Among these tools are integration tables , which are readily available in many books, including the appendices to this one. Also widely available are computer algebra systems (CAS) , which are found on calculators and in many campus computer labs, and are free online.

Tables of integrals

Integration tables, if used in the right manner, can be a handy way either to evaluate or check an integral quickly. Keep in mind that when using a table to check an answer, it is possible for two completely correct solutions to look very different. For example, in Trigonometric Substitution , we found that, by using the substitution x = tan θ , we can arrive at

d x 1 + x 2 = ln ( x + x 2 + 1 ) + C .

However, using x = sinh θ , we obtained a different solution—namely,

d x 1 + x 2 = sinh −1 x + C .

We later showed algebraically that the two solutions are equivalent. That is, we showed that sinh −1 x = ln ( x + x 2 + 1 ) . In this case, the two antiderivatives that we found were actually equal. This need not be the case. However, as long as the difference in the two antiderivatives is a constant, they are equivalent.

Using a formula from a table to evaluate an integral

Use the table formula

a 2 u 2 u 2 d u = a 2 u 2 u sin −1 u a + C

to evaluate 16 e 2 x e x d x .

If we look at integration tables, we see that several formulas contain expressions of the form a 2 u 2 . This expression is actually similar to 16 e 2 x , where a = 4 and u = e x . Keep in mind that we must also have d u = e x . Multiplying the numerator and the denominator of the given integral by e x should help to put this integral in a useful form. Thus, we now have

16 e 2 x e x d x = 16 e 2 x e 2 x e x d x .

Substituting u = e x and d u = e x produces a 2 u 2 u 2 d u . From the integration table (#88 in Appendix A ),

a 2 u 2 u 2 d u = a 2 u 2 u sin −1 u a + C .

Thus,

16 e 2 x e x d x = 16 e 2 x e 2 x e x d x Substitute u = e x and d u = e x d x . = 4 2 u 2 u 2 d u Apply the formula using a = 4 . = 4 2 u 2 u sin −1 u 4 + C Substitute u = e x . = 16 e 2 x u sin −1 ( e x 4 ) + C .
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Computer algebra systems

If available, a CAS is a faster alternative to a table for solving an integration problem. Many such systems are widely available and are, in general, quite easy to use.

Using a computer algebra system to evaluate an integral

Use a computer algebra system to evaluate d x x 2 4 . Compare this result with ln | x 2 4 2 + x 2 | + C , a result we might have obtained if we had used trigonometric substitution.

Using Wolfram Alpha, we obtain

d x x 2 4 = ln | x 2 4 + x | + C .

Notice that

ln | x 2 4 2 + x 2 | + C = ln | x 2 4 + x 2 | + C = ln | x 2 4 + x | ln 2 + C .

Since these two antiderivatives differ by only a constant, the solutions are equivalent. We could have also demonstrated that each of these antiderivatives is correct by differentiating them.

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You can access an integral calculator for more examples.

Using a cas to evaluate an integral

Evaluate sin 3 x d x using a CAS. Compare the result to 1 3 cos 3 x cos x + C , the result we might have obtained using the technique for integrating odd powers of sin x discussed earlier in this chapter.

Using Wolfram Alpha, we obtain

sin 3 x d x = 1 12 ( cos ( 3 x ) 9 cos x ) + C .

This looks quite different from 1 3 cos 3 x cos x + C . To see that these antiderivatives are equivalent, we can make use of a few trigonometric identities:

1 12 ( cos ( 3 x ) 9 cos x ) = 1 12 ( cos ( x + 2 x ) 9 cos x ) = 1 12 ( cos ( x ) cos ( 2 x ) sin ( x ) sin ( 2 x ) 9 cos x ) = 1 12 ( cos x ( 2 cos 2 x 1 ) sin x ( 2 sin x cos x ) 9 cos x ) = 1 12 ( 2 cos 3 x cos x 2 cos x ( 1 cos 2 x ) 9 cos x ) = 1 12 ( 4 cos 3 x 12 cos x ) = 1 3 cos 3 x cos x .

Thus, the two antiderivatives are identical.

We may also use a CAS to compare the graphs of the two functions, as shown in the following figure.

This is the graph of a periodic function. The waves have an amplitude of approximately 0.7 and a period of approximately 10. The graph represents the functions y = cos^3(x)/3 – cos(x) and y = 1/12(cos(3x)-9cos(x). The graph is the same for both functions.
The graphs of y = 1 3 cos 3 x cos x and y = 1 12 ( cos ( 3 x ) 9 cos x ) are identical.
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Use a CAS to evaluate d x x 2 + 4 .

Possible solutions include sinh −1 ( x 2 ) + C and ln | x 2 + 4 + x | + C .

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Key concepts

  • An integration table may be used to evaluate indefinite integrals.
  • A CAS (or computer algebra system) may be used to evaluate indefinite integrals.
  • It may require some effort to reconcile equivalent solutions obtained using different methods.

Use a table of integrals to evaluate the following integrals.

x + 3 x 2 + 2 x + 2 d x

1 2 ln | x 2 + 2 x + 2 | + 2 arctan ( x + 1 ) + C

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1 x 2 + 6 x d x

cosh −1 ( x + 3 3 ) + C

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x · 2 x 2 d x

2 x 2 1 ln 2 + C

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d y 4 y 2

arcsin ( y 2 ) + C

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sin 3 ( 2 x ) cos ( 2 x ) d x

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csc ( 2 w ) cot ( 2 w ) d w

1 2 csc ( 2 w ) + C

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0 1 3 x d x x 2 + 8

9 6 2

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−1 / 4 1 / 4 sec 2 ( π x ) tan ( π x ) d x

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0 π / 2 tan 2 ( x 2 ) d x

2 π 2

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tan 5 ( 3 x ) d x

1 12 tan 4 ( 3 x ) 1 6 tan 2 ( 3 x ) + 1 3 ln | sec ( 3 x ) | + C

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Use a CAS to evaluate the following integrals. Tables can also be used to verify the answers.

[T] d w 1 + sec ( w 2 )

2 cot ( w 2 ) 2 csc ( w 2 ) + w + C

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[T] d w 1 cos ( 7 w )

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[T] 0 t d t 4 cos t + 3 sin t

1 5 ln | 2 ( 5 + 4 sin t 3 cos t ) 4 cos t + 3 sin t |

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[T] x 2 9 3 x d x

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[T] d x x 1 / 2 + x 1 / 3

6 x 1 / 6 3 x 1 / 3 + 2 x 6 ln [ 1 + x 1 / 6 ] + C

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[T] x 3 sin x d x

x 3 cos x + 3 x 2 sin x + 6 x cos x 6 sin x + C

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[T] x 1 + e x 2 d x

1 2 ( x 2 + ln | 1 + e x 2 | ) + C

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[T] 3 5 x 2 x d x

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[T] d x x x 1

2 arctan ( x 1 ) + C

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[T] e x cos −1 ( e x ) d x

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Use a calculator or CAS to evaluate the following integrals.

[T] 0 π / 4 cos ( 2 x ) d x

0.5 = 1 2

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[T] 0 1 x · e x 2 d x

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[T] 0 8 2 x x 2 + 36 d x

8.0

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[T] 0 2 / 3 1 4 + 9 x 2 d x

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[T] d x x 2 + 4 x + 13

1 3 arctan ( 1 3 ( x + 2 ) ) + C

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Use tables to evaluate the integrals. You may need to complete the square or change variables to put the integral into a form given in the table.

d x x 2 + 2 x + 10

1 3 arctan ( x + 1 3 ) + C

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e x e 2 x 4 d x

ln ( e x + 4 + e 2 x ) + C

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cos x sin 2 x + 2 sin x d x

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arctan ( x 3 ) x 4 d x

ln x 1 6 ln ( x 6 + 1 ) arctan ( x 3 ) 3 x 3 + C

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ln | x | arcsin ( ln | x | ) x d x

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Use tables to perform the integration.

d x x 2 + 16

ln | x + 16 + x 2 | + C

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d x 1 cos ( 4 x )

1 4 cot ( 2 x ) + C

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Find the area bounded by y ( 4 + 25 x 2 ) = 5 , x = 0 , y = 0 , and x = 4 . Use a table of integrals or a CAS.

1 2 arctan 10

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The region bounded between the curve y = 1 1 + cos x , 0.3 x 1.1 , and the x -axis is revolved about the x -axis to generate a solid. Use a table of integrals to find the volume of the solid generated. (Round the answer to two decimal places.)

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Use substitution and a table of integrals to find the area of the surface generated by revolving the curve y = e x , 0 x 3 , about the x -axis. (Round the answer to two decimal places.)

1276.14

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[T] Use an integral table and a calculator to find the area of the surface generated by revolving the curve y = x 2 2 , 0 x 1 , about the x -axis. (Round the answer to two decimal places.)

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[T] Use a CAS or tables to find the area of the surface generated by revolving the curve y = cos x , 0 x π 2 , about the x -axis. (Round the answer to two decimal places.)

7.21

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Find the length of the curve y = x 2 4 over [ 0 , 8 ] .

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Find the length of the curve y = e x over [ 0 , ln ( 2 ) ] .

5 2 + ln | 2 + 2 2 1 + 5 |

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Find the area of the surface formed by revolving the graph of y = 2 x over the interval [ 0 , 9 ] about the x -axis.

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Find the average value of the function f ( x ) = 1 x 2 + 1 over the interval [ −3 , 3 ] .

1 3 arctan ( 3 ) 0.416

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Approximate the arc length of the curve y = tan ( π x ) over the interval [ 0 , 1 4 ] . (Round the answer to three decimal places.)

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Questions & Answers

how did you get 1640
Noor Reply
If auger is pair are the roots of equation x2+5x-3=0
Peter Reply
Wayne and Dennis like to ride the bike path from Riverside Park to the beach. Dennis’s speed is seven miles per hour faster than Wayne’s speed, so it takes Wayne 2 hours to ride to the beach while it takes Dennis 1.5 hours for the ride. Find the speed of both bikers.
MATTHEW Reply
420
Sharon
from theory: distance [miles] = speed [mph] × time [hours] info #1 speed_Dennis × 1.5 = speed_Wayne × 2 => speed_Wayne = 0.75 × speed_Dennis (i) info #2 speed_Dennis = speed_Wayne + 7 [mph] (ii) use (i) in (ii) => [...] speed_Dennis = 28 mph speed_Wayne = 21 mph
George
Let W be Wayne's speed in miles per hour and D be Dennis's speed in miles per hour. We know that W + 7 = D and W * 2 = D * 1.5. Substituting the first equation into the second: W * 2 = (W + 7) * 1.5 W * 2 = W * 1.5 + 7 * 1.5 0.5 * W = 7 * 1.5 W = 7 * 3 or 21 W is 21 D = W + 7 D = 21 + 7 D = 28
Salma
Devon is 32 32​​ years older than his son, Milan. The sum of both their ages is 54 54​. Using the variables d d​ and m m​ to represent the ages of Devon and Milan, respectively, write a system of equations to describe this situation. Enter the equations below, separated by a comma.
Aaron Reply
find product (-6m+6) ( 3m²+4m-3)
SIMRAN Reply
-42m²+60m-18
Salma
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bill
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bill
-24m+3+3mÁ^2
Susan
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Amira
I only got 42 the rest i don't know how to solve it. Please i need help from anyone to help me improve my solving mathematics please
Amira
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Aphelele
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Bajemah
-6m(3mA²+4m-3)+6(3mA²+4m-3) =-18m²A²-24m²+18m+18mA²+24m-18 Rearrange like items -18m²A²-24m²+42m+18A²-18
Salma
complete the table of valuesfor each given equatio then graph. 1.x+2y=3
Jovelyn Reply
x=3-2y
Salma
y=x+3/2
Salma
Hi
Enock
given that (7x-5):(2+4x)=8:7find the value of x
Nandala
3x-12y=18
Kelvin
please why isn't that the 0is in ten thousand place
Grace Reply
please why is it that the 0is in the place of ten thousand
Grace
Send the example to me here and let me see
Stephen
A meditation garden is in the shape of a right triangle, with one leg 7 feet. The length of the hypotenuse is one more than the length of one of the other legs. Find the lengths of the hypotenuse and the other leg
Marry Reply
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Abubakar
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Enock
state in which quadrant or on which axis each of the following angles given measure. in standard position would lie 89°
Abegail Reply
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Method
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Enock
what the last part of the problem mean?
Roger
The Jones family took a 15 mile canoe ride down the Indian River in three hours. After lunch, the return trip back up the river took five hours. Find the rate, in mph, of the canoe in still water and the rate of the current.
cameron Reply
Shakir works at a computer store. His weekly pay will be either a fixed amount, $925, or $500 plus 12% of his total sales. How much should his total sales be for his variable pay option to exceed the fixed amount of $925.
mahnoor Reply
I'm guessing, but it's somewhere around $4335.00 I think
Lewis
12% of sales will need to exceed 925 - 500, or 425 to exceed fixed amount option. What amount of sales does that equal? 425 ÷ (12÷100) = 3541.67. So the answer is sales greater than 3541.67. Check: Sales = 3542 Commission 12%=425.04 Pay = 500 + 425.04 = 925.04. 925.04 > 925.00
Munster
difference between rational and irrational numbers
Arundhati Reply
When traveling to Great Britain, Bethany exchanged $602 US dollars into £515 British pounds. How many pounds did she receive for each US dollar?
Jakoiya Reply
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Solomon Reply
Jazmine trained for 3 hours on Saturday. She ran 8 miles and then biked 24 miles. Her biking speed is 4 mph faster than her running speed. What is her running speed?
Zack Reply
d=r×t the equation would be 8/r+24/r+4=3 worked out
Sheirtina
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Source:  OpenStax, Calculus volume 2. OpenStax CNX. Feb 05, 2016 Download for free at http://cnx.org/content/col11965/1.2
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