展开 1/(s(s+3)^2)

解答

展开

\frac{1}{s ( s + 3 ) ^{2}}

\frac{1}{s ^{3} + 6 s ^{2} + 9 s}

求解步骤

\frac{1}{s ( s + 3 ) ^{2}}

(s + 3)^{2} = s^{2} + 6 s + 9

= \frac{1}{s ( s ^{2} + 6 s + 9 )}

乘开

s (s^{2} + 6 s + 9) : s^{3} + 6 s^{2} + 9 s

= \frac{1}{s ^{3} + 6 s ^{2} + 9 s}

e x p an d (x + \frac{1}{4})^{2}

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e x p an d \frac{x}{( x + 2 ) ^{2}}

s im pl i f y (x - 1) (x - 2 - 3) (x - 2 + 3)