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Topic:
how to derive a formula to find the sum of a sequence?
Replies:
4
Last Post:
Nov 3, 2012 3:56 PM




Re: how to derive a formula to find the sum of a sequence?
Posted:
Dec 11, 2010 10:56 AM


You have added 5 times and each time got "6" as the answer. That tells you that the total sum is 5(6)= 30. But you added the sum you want TWICE, the second time reversed. That is, the answer "30" is exactly twice the sum you want.
(By the way, what you wrote: 5 SUM (k+1) k=1
with k+1 rather than k, would be 2+ 3+ 4+ 5+ 6
Reversing those and adding: 2+ 3+ 4+ 5+ 6 6+ 5+ 4+ 3+ 2
You get "8" each of 5 times. What is the sum of that?



