MAT 1235 Calculus II Section 7.1 Integration By Parts .

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MAT 1235 Calculus II Section 7.1 Integration By Parts http://myhome.spu.edu/lauw

Transcript of MAT 1235 Calculus II Section 7.1 Integration By Parts .

Page 1: MAT 1235 Calculus II Section 7.1 Integration By Parts .

MAT 1235Calculus II

Section 7.1

Integration By Parts

http://myhome.spu.edu/lauw

Page 2: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Homework and …

WebAssign 7.1(17 problems, 38 min.)

Page 3: MAT 1235 Calculus II Section 7.1 Integration By Parts .

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Page 4: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Exam II

Be sure to look at the quiz solutions. If you have questions, resolve them

ASAP. Do not wait until the exam day to ask that question.

Get help before it is too late. Exam II is coming up in 8 days.

Page 5: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Preview

The reverse of the product rule

Page 6: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Product Rule

dxxgxfxgxfdxxgxf

xgxfdxxgxfdxxgxf

xgxfdxxgxfxgxf

xgxfxgxfxgxfdx

d

)()()()()()(

)()()()()()(

)()()()()()(

)()()()()()(

Page 7: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Product Rule

dxxgxfxgxfdxxgxf

xgxfdxxgxfdxxgxf

xgxfdxxgxfxgxf

xgxfxgxfxgxfdx

d

)()()()()()(

)()()()()()(

)()()()()()(

)()()()()()(

Page 8: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Definition of Antiderivatives

dxxgxfxgxfdxxgxf

xgxfdxxgxfdxxgxf

xgxfdxxgxfxgxf

xgxfxgxfxgxfdx

d

)()()()()()(

)()()()()()(

)()()()()()(

)()()()()()(

Page 9: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Rationale

dxxgxfxgxfdxxgxf )()()()()()(

The integral on the right hand side is easier to evaluate than the one on the left hand side

Easier

Difficult

Page 10: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Rationale

dxxgxfxgxfdxxgxf )()()()()()(

The integral on the right hand side is easier to evaluate than the one on the left hand side

Easier

Difficult

xdxxxxdxx sinsincos

Page 11: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Alternative Form

dxxgxfxgxfdxxgxf )()()()()()(

vduuvudv

dxxgdvdxxfdu

xgvxfu

have We

)( ,)(Then

)( ),(Let

Page 12: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Integration By Parts

( ) ( ) ( ) ( ) ( ) ( )

( ) ( ) ( ) ( ) ( ) ( )b b

b

aa a

f x g x dx f x g x f x g x dx

udv uv vdu

f x g x dx f x g x f x g x dx

Page 13: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Example 1

cosx xdx

Page 14: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Example 1(Analysis) vduuvudv

In order to use IBP, we need to choose and

One possible choice is xdx dvxu cos ,

cosx xdx

Page 15: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Example 1(Analysis)

In order to use IBP, we need to choose and

One possible choice is

xdx dvxu cos ,Let

cosx xdx

vduuvudv

Page 16: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Example 1(Analysis)

Now, we need to find and

xdxx cos

x

xdxvdxdu

xdx dvxu

sin

cos , Then,

cos , Let

vduuvudv

Page 17: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Example 1(Analysis)

Now, we need to find and

xdxx cos

x

xdxvdxdu

xdx dvxu

sin

cos , Then,

cos , Let

vduuvudv

Page 18: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Example 1

cos

sin sin

x xdx

x x xdx

x

xdxvdxdu

xdx dvxu

sin

cos , Then,

cos , Let

vduuvudv

Page 19: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Example 1

cos

sin sin

x xdx

x x xdx

vduuvudv

x

xdxvdxdu

xdx dvxu

sin

cos , Then,

cos , Let

What if?

B

Page 20: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Example 1 vduuvudv

What if?

2 ,sin Then,

,cos Let 2x

xdxvxdxdu

xdx dvxu

cos

cos

x xdx

x xdx

Page 21: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Example 2xxe dx

vduuvudv

xxe dx

Page 22: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Expectations

All supporting steps are required and done on the right side.

Page 23: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Example 32

1

ln xdx

vduuvudv

2

1

ln xdx

Page 24: MAT 1235 Calculus II Section 7.1 Integration By Parts .

Example 4

cosxe xdx

vduuvudv

cosxe xdx xe