把六分之一加十二分之一加二十四分之一加四十八分之一简便方法解:原式=1/6+1/12+1/24+1/48=1/6+1/12+1/24+1/48+1/48-1/48=1/6+1/12+1/24+1/24-1/48=...=1/3-1/48=5/16
解上式=1/2×【1/2-1/4+1/4-1/6+……+1/2n-1/(2n+2)】=1/2×【1/2-1/(2n+2)】=1/2×n/(2n+2)=n/(4n+4)