1+1⼀2+(1⼀2)^2+(1⼀2)^3+(1⼀2)^4+(1⼀2)^5+..........+(1⼀2)^2008

2024-12-21 16:58:34
推荐回答(2个)
回答1:

1+1/2+(1/2)^2+(1/2)^3+(1/2)^4+(1/2)^5+..........+(1/2)^2008
=(1-(1/2)^2009)/(1-1/2)
=2(1-(1/2)^2009)

回答2:

发现 这个实际上是以首项为1,公比为1/2的等比数列的和
Sn=a1(1-q^n)/(1-q)
1+1/2+(1/2)^2+(1/2)^3+(1/2)^4+(1/2)^5+..........+(1/2)^2008
=1*(1-0.5^2009)(1-0.5)
=2(1-0.5^2009)