tính
($\frac{1}{3}$ $\sqrt{\frac{1}{2}}$ -$\frac{2}{3}$$\sqrt{\frac{3}{2}}$ +$\frac{2}{7}$$\sqrt{\frac{1}{6}}$ ) : ($\frac{2}{7}$$\sqrt{\frac{1}{8}}$ )
giúp mk vs
tính
($\frac{1}{3}$ $\sqrt{\frac{1}{2}}$ -$\frac{2}{3}$$\sqrt{\frac{3}{2}}$ +$\frac{2}{7}$$\sqrt{\frac{1}{6}}$ ) : ($\frac{2}{7}$$\sqrt{\frac{1}{8}}$ )
giúp mk vs
Đáp án:
`(1/3\sqrt{1/2}-2/3\sqrt{3/2}+2/7\sqrt{1/6}):(2/7\sqrt{1/8})`
`=(\sqrt{1/9*1/2}-\sqrt{4/9*3/2}+\sqrt{4/49*1/6}):\sqrt{4/49*1/8}`
`=(\sqrt{1/18}-\sqrt{2/3}+\sqrt{2/147}):\sqrt{1/98}`
`=(\sqrt{1/18}-\sqrt{2/3}+\sqrt{2/147})*\sqrt{98}`
`=\sqrt{49/9}-\sqrt{196/3}+\sqrt{4/3}`
`=7/3-14/\sqrt{3}+2/\sqrt{3}`
`=7/3-12/\sqrt{3}`
`=(7-12\sqrt{3})/3.`
Đáp án: + Giải thích các bước giải:
`(1/3\sqrt{2/3}-2/3\sqrt{3/2}+2/7\sqrt{1/6})\div(2/7\sqrt{1/8})`
`= (1/3\sqrt{1/2}-2/3\sqrt{3/2}+2/7\sqrt{1/6})\div1/(7\sqrt{2})`
`= 1/(3\sqrt{2}) – \sqrt{6}/3 + \sqrt{2}/(7\sqrt{3}) \div 1/(7\sqrt{2})`
`= (1/(\sqrt{2}*3) – \sqrt{6}/3 + \sqrt{2}/(\sqrt{3}*7))\sqrt{2} * 7 \div 1`
`= 7\sqrt{2}(7\sqrt{3}-36)/(21\sqrt{6}) \div1`
`= (7\sqrt{3}-36)/(21\sqrt{6})\sqrt{2}*7`
`= ((7\sqrt{3}-36)\sqrt{2}*7)/(21\sqrt{6})`
`= (\sqrt{2}(7\sqrt{3}-36))/(3\sqrt{2}\sqrt{3})`
`= (7\sqrt{3}-36)/(3\sqrt{3})`
`= (7-12\sqrt{3})/3`