Question 743334:  Some sequences involve a pattern but are not arithmetic. Find the sum of the first 72-terms in the sequence 6,8,2,..., where An=(A(n-1))-(A(n-2))(The last term ia equal to the (last term minus 1) minus (the last term minus 2))
 
So, An is the last term in the sequence n= the total terms in the sequence (72)
 
Thank you 
 Answer by Edwin McCravy(20064)      (Show Source): 
You can  put this solution on YOUR website! 
The first 9 terms of the sequence are
6, 8, 2,-6,-8,-2, 6, 8, 2,-6,-8,-2 which have sum 0.
The next 9 terms are the same, which also have sum 0, etc. etc.
72 terms is 8 groups of those same 9 terms, each having sum 0,
Therefore the entire sum is 0.
Edwin  
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