Write Expression In Partial Fraction

x^2/(x-1)(x+1) = x^2/x^2-1 = 1,-1

Therefore,

x^2/(x-1)(x+1) = 1 + -1/(x-1)(x+1)

-1/(x-1)(x+1) = A/(x-1) + B/(x+1)

-1 = Ax + A + Bx - B

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

A+B = 0, B = -A

-1 = A - B = A - (-A) = 2A

-1 = 2A, A = -1/2,

B = -(-1/2) = 1/2

Therefore,

x^2/(x-1)(x+1) = 1 - 1/2(x-1) + 1/2(x+1)

But somehow the answer given to me is

x^2/(x-1)(x+1) = 1 **+** 1/2(x-1) **-** 1/2(x+1)

Not sure which step I doing wrong, please help me on this. Thank you.

Re: Write Expression In Partial Fraction

Hello, gilagila!

We have: .

Then: .

. . . . . .

Let

Let

Therefore: .

Re: Write Expression In Partial Fraction

Quote:

Originally Posted by

**Soroban**

Just want to check, how you change to this ??

Re: Write Expression In Partial Fraction

Quote:

Originally Posted by

**gilagila** Just want to check, how you change to this ??

He subtracted 1 from the numerator and at the same time added it. This does not make any "change" to expression.

http://latex.codecogs.com/gif.latex?x^2 http://latex.codecogs.com/gif.latex?x^2http://latex.codecogs.com/gif.latex?...pace;-1+1

Re: Write Expression In Partial Fraction

oic, thanks for explanation