展开 9/((1-x)(1+2x)^2)

解答

展开

\frac{9}{( 1 - x ) ( 1 + 2 x ) ^{2}}

\frac{9}{- 4 x ^{3} + 3 x + 1}

求解步骤

\frac{9}{( 1 - x ) ( 1 + 2 x ) ^{2}}

(1 + 2 x)^{2} = 1 + 4 x + 4 x^{2}

= \frac{9}{( - x + 1 ) ( 4 x ^{2} + 4 x + 1 )}

乘开

(1 - x) (1 + 4 x + 4 x^{2}) : - 4 x^{3} + 3 x + 1

= \frac{9}{- 4 x ^{3} + 3 x + 1}

e x p an d \frac{1}{2 ( n ^{2} - n )}

e x p an d cos (x) d y - (2 y sin (x) - 3) d x

e x p an d \frac{3 s + 5}{( s + 1 ) ( s ^{2} + 3 s + 2 )}

e x p an d \frac{x ^{4} - 3 x ^{2}}{( x ^{2} - 1 ) ^{2}}

s im pl i f y (x - \frac{3}{4}) (x + \frac{3}{4})