展开 (5(3+sqrt(21)))/6

解答

展开

\frac{5 ( 3 + 21 )}{6}

\frac{5}{2} + \frac{5 7}{2 3}

十进制

6.31881 \dots

求解步骤

\frac{5 ( 3 + 21 )}{6}

乘开

5 (3 + 21) : 15 + 521

= \frac{15 + 5 21}{6}

使用分式法则:

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

\frac{15 + 5 21}{6} = \frac{15}{6} + \frac{5 21}{6}

= \frac{15}{6} + \frac{5 21}{6}

消掉

\frac{15}{6} : \frac{5}{2}

= \frac{5}{2} + \frac{5 21}{6}

消掉

\frac{5 21}{6} : \frac{5 7}{2 3}

= \frac{5}{2} + \frac{5 7}{2 3}

e x p an d \frac{( 8 + x ) ( x ^{2} + x - 2 )}{2}

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

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

e x p an d 1 - e^{10 k - 10 (a_{0} + 0.00512)}

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