Question

How can the fraction (s - 1) / (s^2 + 4)^2 be decomposed into simple fractions? The answer would be the one at this link, http://i.imgur.com/YR1ntFu.jpg, but I'm not sure I understand how the last two fractions come about.

Answer 1

me neither
usually see this as
\[\frac{As+B}{s^2+4}+\frac{Cs+
d}{(s^2+4)^2}\]

Answer 2

in fact i am really lost because you can decompose this instantly as
\[\frac{s}{(x^2+4)^2}-\frac{1}{(x^2+4)^2}\]