請問此題的解題過程???感激~?

2016-01-16 2:14 pm

回答 (1)

2016-01-17 12:17 am
✔ 最佳答案
Sol
設a=10^(logx)
loga=logx
a=x
So
1+10^log(5/3)+10^[2(log5/3)]+…+10^[(n-1)log(5/3)]
=1+log(5/3)+2log(5/3)+…+(n-1)log(5/3)
=[1+(n-1)](n-1)/2*log(5/3)
=n(n-1)(log5-log3)/2
=n(n-1)(1-0.3010-0.4771)/2
=0.11095n(n-1)>2007
134*133*0.11095=1977.35
135*134*0.11095=2007.0855
最小n=135


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