展开 (n-1)!*((n+1)!-n!)

解答

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(n - 1)! \cdot ((n + 1)! - n!)

(n - 1)! (n + 1)! - n! (n - 1)!

求解步骤

(n - 1)! ((n + 1)! - n!)

使用分配律:

a (b - c) = ab - a c

a = (n - 1)!, b = (n + 1)!, c = n!

= (n - 1)! (n + 1)! - (n - 1)! n!

= (n - 1)! (n + 1)! - n! (n - 1)!

e x p an d (f (x) = x^{2} + 8 x + 13,) (,)

e x p an d - \frac{1}{x ( h + x )}

e x p an d 3 i - 2 j (1, - 2)

e x p an d \frac{1 - x ( ln ( x ) + c )}{x ^{2}}

e x p an d \frac{[ ( x - 1 ) ( x + 3 ) ]}{( x - 2 )}