展开 (x*(x-1))/2

解答

展开

\frac{x \cdot ( x - 1 )}{2}

\frac{x ^{2}}{2} - \frac{x}{2}

求解步骤

\frac{x ( x - 1 )}{2}

乘开

x (x - 1) : x^{2} - x

= \frac{x ^{2} - x}{2}

使用分式法则:

\frac{a \pm b}{c} = \frac{a}{c} \pm \frac{b}{c}

\frac{x ^{2} - x}{2} = \frac{x ^{2}}{2} - \frac{x}{2}

= \frac{x ^{2}}{2} - \frac{x}{2}

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

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

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

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

e x p an d 5 x (- 8 + 10) + x (- 410 + 5)