展开 ((2k+1)(k+2))/2

解答

展开

\frac{( 2 k + 1 ) ( k + 2 )}{2}

k^{2} + \frac{5 k}{2} + 1

求解步骤

\frac{( 2 k + 1 ) ( k + 2 )}{2}

乘开

(2 k + 1) (k + 2) : 2 k^{2} + 5 k + 2

= \frac{2 k ^{2} + 5 k + 2}{2}

使用分式法则:

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

\frac{2 k ^{2} + 5 k + 2}{2} = \frac{2 k ^{2}}{2} + \frac{5 k}{2} + \frac{2}{2}

= \frac{2 k ^{2}}{2} + \frac{5 k}{2} + \frac{2}{2}

使用法则

\frac{a}{a} = 1

\frac{2}{2} = 1

= \frac{2 k ^{2}}{2} + \frac{5 k}{2} + 1

数字相除:

\frac{2}{2} = 1

= k^{2} + \frac{5 k}{2} + 1

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

\frac{d}{d t} ((x) (6 t^{2} - t^{3}))

\frac{d}{d x} ((y^{3}) c (x - c)^{2})

e x p an d (x^{2} - 2 x - 3)^{5}

e x p an d (8 x - 20) \circ