improperiutegrats - university of california, berkeley
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ImproperIutegratsHim Extend definition of definite integral to
deal with infinite length intervals and
vertical asymptotesInstructiveE What is the area under y IT over Cl
A real
y Iz so f number so cannot directlyuse fundamental theorem
a
Clever attachArea 1 find Area I
y zArea I dx 4 1 Ii I Area E Lim l t I
i t a t a
Definition Type 1 Improper Integrals
Ay Jatexidx if Tatem da Say integral isconvergent F limit
b b exists Divergent Ft not31 ft Gc dx if I text dxt Convergent meansconvergent both convergent area is finite
4 If dx Jota xidx
Example J doc
dx fits dx fig aretanitt t
dx fits FI dx fiI.zaretanitl Ia
J da it c convergent
Instructive what is area under y r over co 13Example
Area Iir
f y Fx has vertical asymptote at
1 x o Net a definite integralO li
Area I fig Area
µ Area ftp.dx zrxt2 ZTEt
Area E fig 02 2 re 2
Definition Type 2 Improper Integrals
Ay IF t has a vertical asymptote at a
Convergenttext doc fifa dlimit exists
B If f has a vertical asymptote at b
b t
HM doc fig fax da Convergentb a
limit exists
4 It 1 has a vertical asymptote at asccb
text dx afcxgdx04 da
T t TA B
convergentBoth limitsexist
ExampleVertical asymptote at a o
f da cannot apply fundamentali
Very wrong I dx I z
theorem
comeet Io dx Io j dx no l
f dx divergent
Usual definiteUseful Fact integral
b fOE g ca E 7cal o EJagan du E tea da
f yfArea E E Areal 1
Ta b
knowing this we deduce
Comparison Theorems For Improper Integrals
Assume 0 E g Gal E 7cal Integrals
dxf fcxidxffgc.edu Jacfcxidx Convergent
Tag Gilda cxidx ex d agcxidx Convergent
and
Jag Gilda cxidx exidx Jaga'd
fCx1dx f cxidx cxidx 9 aid
Example e da convergent or divergent
Problem Je da
o E e E e ou C l
te dx fig e doc fig e I
Lim et
et
e I convergentt s
Don't know exacte da eut value