展开 (3k(k+1))/2+(k+1)

解答

展开

\frac{3 k ( k + 1 )}{2} + (k + 1)

\frac{3 k ^{2}}{2} + \frac{3 k}{2} + k + 1

求解步骤

\frac{3 k ( k + 1 )}{2} + (k + 1)

去除括号:

(a) = a

= \frac{3 k ( k + 1 )}{2} + k + 1

乘开

3 k (k + 1) : 3 k^{2} + 3 k

= \frac{3 k ^{2} + 3 k}{2} + k + 1

使用分式法则:

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

\frac{3 k ^{2} + 3 k}{2} = \frac{3 k ^{2}}{2} + \frac{3 k}{2}

= \frac{3 k ^{2}}{2} + \frac{3 k}{2} + k + 1

e x p an d (2 x - 3 y + c) (4 z - x^{\circ} + 2 x y)

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

e x p an d (2 x y + x^{2} + x^{4}) d x

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

e x p an d 60 \cdot \frac{6}{8}