求(1+1/2)(1+1/4)(1+1/16).3..(1+1/2*2n)的值
问题描述:
求(1+1/2)(1+1/4)(1+1/16).3..(1+1/2*2n)的值
1/2=2分之1,以此类推1/2*2n =2的2n分之1
答
(1+1/2)(1+1/4)(1+1/16).(1+1/2^2n)
=(1+1/2)(1+1/4)(1+1/16).(1+1/2^2n)(1-1/2)/(1-1/2)
=[1 -1/2^(2n+1)]/(1/2)
=2-1/2^2n
if n取极限,
则,原式等于2