0
   

Partial fraction

 
 
Lingqi
 
Reply Wed 1 Oct, 2008 03:46 pm
Express (x^2+23)/((x+1)^3(x-2)) in partial fraction
  • Topic Stats
  • Top Replies
  • Link to this Topic
Type: Question • Score: 0 • Views: 1,697 • Replies: 5
No top replies

 
Ragman
 
  1  
Reply Wed 1 Oct, 2008 04:31 pm
@Lingqi,
Let me guess -- you want us to do totally your homework for you without showing anything you have done to try and solve ther problem on your own? Is that about right?
Lingqi
 
  1  
Reply Thu 2 Oct, 2008 06:17 am
@Ragman,
No, its not that i hv done it but i'm lazy to type my working coz 2 long..My working is wrong so i jz wan 2 knw anybody knw alternate method to solve it..Jz doing some research..If got new method i learn more..If nt nevermind..Anyway my teacher wil explain it..Dont u think by doing this u might find easier ways to solve this questions than ur tcer method..I'm juz doing comparing..No offence..Sorry if i hv say o done anything wrng
0 Replies
 
Brandon9000
 
  1  
Reply Thu 2 Oct, 2008 09:07 am
@Lingqi,
Lingqi wrote:

Express (x^2+23)/((x+1)^3(x-2)) in partial fraction

In general, a fraction with n linear factors of x+1 in the denominator can be decomposed as follows:

A1/(x + 1) + A2/(x+1)^2 +...+ An/(x+1)^n
0 Replies
 
Miller
 
  1  
Reply Thu 2 Oct, 2008 09:29 am
@Lingqi,
Lingqi wrote:

Express (x^2+23)/((x+1)^3(x-2)) in partial fraction


How come you didn't say "Please"?
0 Replies
 
Lingqi
 
  1  
Reply Fri 3 Oct, 2008 05:46 am
Ok please anybody o miller can you all have a look what i have done..(x^2+23)/((x+1)^3(x-2))=a/(x+1)^3+ b/(x+1)^2 + c/(x+1) + d/(x-2)

=a(x-2) +b(x+1)(x-2)+ c(x+1)^2(x-2)+ d(x+1)^3

=(c+d)x^3+ (b+3d)x + (a-b-3c+3d)x^2 + (-2a-2b-2c+d)

comparing coefficient:

c+d=0 ->eqn 1, a-b-3c+3d=0 ->eqn 2, -2a-2b-2c+d=23 ->eqn 3, b+3d=1 ->eqn 4

put eqn 2=eqn 3: 3a+b-c+2d-23=0 ->eqn 5

put eqn 1=eqn 4: c+d= b+3d-1

-2d+ c- b+ 1=0 ->eqn 6

eqn 5 + eqn 6:

3a-22=0

3a=22

a=(22)/3

put a into eqn 5, b- c+ 2d-1=0

put eqn 1 into eqn 5 where c= -d, b-(-d)+2d-1=0

b+3d=1

please anybody know how to continue the rest & where i got wrong because the real answer is 1/(x-2) - 1/(x+1) -2/(x+1)^2 -8/(x+1)^3
0 Replies
 
 

Related Topics

Amount of Time - Question by Randy Dandy
Statistics - Question by ekkline
Math of infinity - Discussion by dalehileman
Probability Question. - Discussion by babemomlover
Do I make the mistake? - Question by tetupioxi
 
  1. Forums
  2. » Partial fraction
Copyright © 2024 MadLab, LLC :: Terms of Service :: Privacy Policy :: Page generated in 0.03 seconds on 04/24/2024 at 11:56:54