jy3514953
幼苗
共回答了394个问题 举报
s=(1+1/2)(1+1/2^2)(1+1/2^4)...(1+1/2^(2^n))
(1-1/2)s=(1-1/2)(1+1/2)(1+1/2^2)(1+1/2^4)...(1+1/2^(2^n))
=(1-1/2^2)(1+1/2^2)(1+1/2^4)(1+1/2^8)...(1+1/2^(2^n))
=(1-1/2^4)(1+1/2^4)(1+1/2^8)...(1+1/2^(2^n))
=(1-1/2^(2^n+2))
s=2(1-1/2^(2^n+2))
n趋于无穷,s趋于2,故(1+1/2)(1+1/2^2)(1+1/2^4)...=2
1年前
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