Heres my attempt:

9B+3C+D=1

9A+6B+C=0

6A+B+3C+D=0

A+C=0

This is what I get for A, B C, and D

Where did I go wrong?

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- August 28th 2010, 09:58 AMyoman360partial fraction decomposition help

**Heres my attempt:**

9B+3C+D=1

9A+6B+C=0

6A+B+3C+D=0

A+C=0

**This is what I get for A, B C, and D**

**Where did I go wrong?** - August 28th 2010, 10:23 AMUnknown008
It seems you missed something while solving simultaneously...

Anyway, if you take from here:

Putting x = -3 cancels A, B and C all at once, giving:

And

- August 28th 2010, 10:36 AMyoman360
your right i made one tiny mistake which messed up the whole thing. >.<

- August 28th 2010, 10:38 AMUnknown008
I agree. One slight mistake can ruin the whole thing since there are so many 'variables' to find...

Anyway, I then used wolframalpha and got the partial fractions:

http://www.wolframalpha.com/input/?i=\frac{1}{(x^2%2B1)(x%2B3)^2}