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# C4 Partial Fractions- help! watch

1. Write in the form where A, B, C and x are constants to be found.

So far, I've found C to be -11 and B to be 12, but B is apparently 14...

I subbed in C=-11 and then added that to both sides so I was left with only A and B terms on the RHS. I then subbed in x=0 and then x=1 to form two simultaneous equations from which I found that B was 12...Any ideas?
2. the degree of the numerator is greater than the degree of the denominator, so first Id divide out (you get an ax+b in doing this) this simplifies things with the remaining rational fraction, where you only have to use ascending powers of (x+1) (the line you have above is fine, and youll have what "A" is already...

equate x equal to -1 to get C, then choose an arbitrary x to get B

(EDIT) but, you can "guess" what B and C are by factorising the "remainder" i.e.

3. (Original post by bobbricks)
Write in the form where A, B, C and x are constants to be found.

So far, I've found C to be -11 and B to be 12, but B is apparently 14...

I subbed in C=-11 and then added that to both sides so I was left with only A and B terms on the RHS. I then subbed in x=0 and then x=1 to form two simultaneous equations from which I found that B was 12...Any ideas?
Comparing the coefficients of x^2 will immediately give you the value of A. Then coefficients of x will give you B
4. (Original post by Hasufel)
the degree of the numerator is greater than the degree of the denominator, so first Id divide out (you get an ax+b in doing this) this simplifies things with the remaining rational fraction, where you only have to use ascending powers of (x+1) (the line you have above is fine, and youll have what "A" is already...

equate x equal to -1 to get C, then choose an arbitrary x to get B

(EDIT) but, you can "guess" what B and C are by factorising the "remainder" i.e.

(Original post by brianeverit)
Comparing the coefficients of x^2 will immediately give you the value of A. Then coefficients of x will give you B
Thanks you two, I've finally managed to do it!

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Updated: November 21, 2013
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