This is probably a "basic" question, but I can't seem to remember how to do partial fractions problems where there is only a 1 in the numerator.(adsbygoogle = window.adsbygoogle || []).push({});

For example (just making this up), let's say I have:

1/s(s+4)(s+5)

So what I'd do is 1/s(s+4)(s+5) = A/s + B/(s+4) + C/(s+5) as one would expect, but this can't be right, correct? It seems a lot of coefficients don't "work out."

For example, after doing cross multiplications and combining terms, you would basically get:

For s^2 terms: (A+B+C) = 0 [1]

For s terms: (6A + 5B + 4C) = 0 [2]

For no-s terms: 5A = 1 [3]

Then putting [3]--> [1], then getting B=-C - 1/5, and putting that in [2]. You'll end up with A being equal to 1/5, and C being equal to -1/5. Plug this all into [1], so then that means B is equal to zero. What am I missing here? Is this right?

Matlab says it should be C=-1 and B=1, which means that A is zero then? Huh? I am pretty confused.

Thanks.

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# Partial fractions - having 1 in the numerator?

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