\(a,\) \(A=\dfrac{2}{3}+\dfrac{2}{6}+\dfrac{2}{\text{1}2}+\dfrac{2}{24}+\dfrac{2}{48}+\dfrac{2}{96}+\dfrac{2}{\text{1}92}\) \(A\times2=\left(\dfrac{2}{3}+\dfrac{2}{6}+\dfrac{2\text{ }}{\text{1}2}+\dfrac{2}{24}+\dfrac{2}{48}+\dfrac{2}{96}+\dfrac{2}{\text{1}92}\right)\times2\)
\(A\times2=\dfrac{4}{3}+\dfrac{2}{3}+\dfrac{2}{6}+\dfrac{2}{\text{1}2}+\dfrac{2}{24}+\dfrac{2}{48}+\dfrac{2}{96}\)
\(A\times2-A=\left(\dfrac{4}{3}+\dfrac{2}{3}+\dfrac{2}{6}+\dfrac{2}{\text{1}2}+\dfrac{2}{24}+\dfrac{2}{48}+\dfrac{2}{96}\right)-\left(\dfrac{2}{3}+\dfrac{2}{6}+\dfrac{2}{\text{1}2}+\dfrac{2}{24}+\dfrac{2}{48}+\dfrac{2}{96}+\dfrac{2}{\text{1}92}\right)\)
\(A=\dfrac{4}{3}+\dfrac{2}{3}+\dfrac{2}{6}+\dfrac{2}{\text{1}2}+\dfrac{2}{24}+\dfrac{2}{48}+\dfrac{2}{96}-\dfrac{2}{3}-\dfrac{2}{6}-\dfrac{2}{\text{1}2}-\dfrac{2}{24}-\dfrac{2}{48}-\dfrac{2}{96}-\dfrac{2}{\text{1}92}\)
\(A=\dfrac{4}{3}-\dfrac{2}{\text{1}92}\)
\(A=\dfrac{\text{1}27}{96}\)
`a. 2/3 +2/6+2/12+2/24+2/48 +2/96+2/192`
`@`Đặt `A=2/3 +2/6+2/12+2/24+2/48 +2/96+2/192`
`A=2 xx(1/3 +1/6 +1/12+1/24+1/48+1/96+1/192)`
`A=2 xx(1/(1xx3) + 1/(3xx2) + 1/(3xx4) + 1/(4xx6) +1/(8xx6) + 1/(8xx12) +1/(12xx16) )`
`A=2/3 +2xx(1/2 - 1/4) +2xx (2/24 + 2/ 48) :2 +1/2 xx (4/96 + 4/192)`
`A=2/3 + 2xx 1/4 + 2 xx 1/8 : 2+ 1/2 xx 1/16`
`A=2/3 + 1/2 + 1/8 + 1/32`
`A=4/6 +3/6 +1/8 +1/32`
`A=7/6 + 1/8 +1/32`
`A=31/24 +1/32`
`A=127/96`
a,a, A×2=(23+26+2 12+224+248+296+2192)×2A×2=(23+26+2 12+224+248+296+2192)×2
A×2−A=(43+23+26+212+224+248+296)−(23+26+212+224+248+296+2192)A×2−A=(43+23+26+212+224+248+296)−(23+26+212+224+248+296+2192)
A=43−2192A=43−2192
