展开 1/((2n-1)(2n+1))

解答

展开

\frac{1}{( 2 n - 1 ) ( 2 n + 1 )}

\frac{1}{4 n ^{2} - 1}

求解步骤

\frac{1}{( 2 n - 1 ) ( 2 n + 1 )}

乘开

(2 n - 1) (2 n + 1) : 4 n^{2} - 1

= \frac{1}{4 n ^{2} - 1}

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

e x p an d y (2 x^{2} - x y + y^{2}) d x - x^{2} (2 x - y) d y

e x p an d (e^{x} + 1)^{3}

e x p an d (6 x + y^{2}) d x + y (2 x - 3 y) d y

s im pl i f y (3 y - 5 i)^{2}