Sn=2+2^2+2^3+2^4+2^5+2^6+2^7+……2^n
2*Sn=2^2+2^3+2^4+2^5+2^6+2^7+……2^n+2^(n+1)
Sn=2*Sn-Sn
=2^(n+1)-2 (中间部分消掉)
错位相减法是常用的方法.
数学指数定理证明
数学指数定理证明
证明2+2^2+2^3+2^4+2^5+2^6+2^7+……2^n=2^(n+1)-2
证明2+2^2+2^3+2^4+2^5+2^6+2^7+……2^n=2^(n+1)-2
数学人气:222 ℃时间:2020-04-14 03:14:24
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