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# Partial fractions C4 -is this right? watch

1. (x+1)/ (Xsquared -4)

Does it become (x+1)/ (x+2)(x-2)

Then x+1 = A(x-2) + B(x+2)

Then let x=2 Get B as 3/4
Then let x= -2 Get A as 1/4

1/4(x+2) - 3/4(x-2)

But when i work backwords isn't right

Thanks
2. Is B 3/4 or -3/4?
3. (Original post by ViolinGirl)
(x+1)/ (Xsquared -4)

Does it become (x+1)/ (x+2)(x-2)

Then x+1 = A(x-2) + B(x+2)

Then let x=2 Get B as 3/4
Then let x= -2 Get A as 1/4

1/4(x+2) - 3/4(x-2)

But when i work backwords isn't right

Thanks
in bold. one is different from the other
4. (Original post by ian.slater)
Is B 3/4 or -3/4?
Sorry, typing error. It is 3/4.

But is the method right?
5. (Original post by mathz)
in bold. one is different from the other
It is 3/4 so will be +3/4. Sorry, typed it wrong.

But just worked back again, and it still isn't going back to original fraction
6. Yes it's right. 0.25/(x+2) + 0.75/(x-2)
7. The above user is correct.

Check wolfram alpha to verify.

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