Question

can someone show me how to use partial fractions in integration please? it confuses me...i think i did well in this during the algebra course...i dont know lol maybe i need a refresher :DDD

Answer 1

partial fractions is a technique used to rewrite an argument

Answer 2

its easier to follow if you have a specific example to work thru tho

Answer 3

\[\frac 1 {x(x-1)}=\frac{A}{x} +\frac B {x-1}\]

Answer 4

if you were asked to integrate the first expression, it would be easiest to convert to the second expression before integration

Answer 5

then to solve for A and B

Answer 6

then to integrate

Answer 7

hmm well how about problems with trig sub AND partial fractions?

Answer 8

yuk

Answer 9

yuk?

Answer 10

sorry that sort of problem seams like a nightmare

Answer 11

i know :/

Answer 12

im sure there are some people who would like that sort of problem but i am not one of them

Answer 13

those guys who gave me brutal problems on the last question might...people like @lalaly @amistre64 and @FoolForMath ? :P

Answer 14

hi:D

Answer 15

hello :) i'm lgbasallote. nice to meet you lalaly

Answer 16

lol nice to meet you tooo

Answer 17

enough of the getting-to-know...can you teach me how to solve trig sub + partial fractions combined? you're pretty good in brutal calculus so i thought ill ask you

Answer 18

lalaly where are you from?

Answer 19

and how did get the "99"? :p

Answer 20

lol tai ive been on os for more than a year ... and i solved so many questions :D ... lg id be happy to ...

Answer 21

partial fractions in integration, is it definite or indefinite?

Answer 22

remember to + C for the unknown

Answer 23

and plug in co-ords to find C

Answer 24

yay for lana \m/ indefinite would be nice Tai since definite just comes from indef

Answer 25

well...just use the power and divide by it?

Answer 26

let's say x^1/4 becomes (x^5/4)/(5/4) which is 4/5(x^5/4)

Answer 27

+ C

Answer 28

but that's the power formula..not the partial fractions

Answer 29

what do you mean by "partial fractions"?

Answer 30

partial fractions,...uhh how are they explained....i dunno lol...

Answer 31

lol >_>

Answer 32

the denominator is not factorisable, give me an example to work with plox

Answer 33

that totally depicts my lack of mastery :P anyway...maybe a sample from the legendary @lalaly can hellp us both...

\(\Large \int \frac{e^x}{(e^x - 1)(e^x + 3)} dx\)

Answer 34

lga 1st u have to put e^x=t

Answer 35

uh-huh...

Answer 36

\(\large \int \frac{dt}{(t-1)(t+3)}\)

Answer 37

eww

Answer 38

ya gud lga

Answer 39

so it's \(\large \frac{A}{t-1} + \frac{B}{t+3}\)

Answer 40

i dont think this is gonna have trig subs though...

Answer 41

i never use partail formula ..i use always my trick to solve dis types of question

Answer 42

mind sharing?

Answer 43

yeah lol

Answer 44

i'm kinda stuck

Answer 45

pro people ^_^

Answer 46

you guys all @ uni?

Answer 47

i think me and lalaly are...gurvinder though i think isnt are you?

Answer 48

no, i'm lazy

Answer 49

i'm 17, wbu guys?

Answer 50

hmmm lana's taking a long time..must be some heck of a latex lol

Answer 51

and she's suddenly gone

Answer 52

lol

Answer 53

committed suicide

Answer 54

just kidding

Answer 55

A/(t−1)+B/(t+3)

Answer 56

is that the f'(x)?

Answer 57

or f(x)?

Answer 58

A(t-1)^-1 + B(t+3)^-1 --> -A(t-1)^-2 -B(t+3)^-2

Answer 59

@gurvinder what is your trick?

Answer 60

can you apply to :
\[\frac1{x(x−1)}\]

Answer 61

he's joking, there's no trick

Answer 62

oh, lame

Answer 63

yeah...:(

Answer 64

i think it is the cover up method thing

Answer 65

i wish there were shortcuts to mathematics...

Answer 66

-drinks coffee-

Answer 67

choose C alway

Answer 68

@lgbasallote I'd be happy to help you with such an integration problem if you still need the help

Answer 69

well i'll be happy to be helped too @TuringTest after all i still do not know how to it haha lol =))

Answer 70

ya tia have a trick ok..........i going to tell u all