Question 933241: For each sequence, find a closed formula for the general term, a sub n.
1. 53,477,4293,38637,347733,... a sub n =
2. 2,5,10,17,26,...a sub n =
3. -2,-8,-18,-32,-50,...a sub n =
Help would truly be appreciated!
Answer by Edwin McCravy(20056)   (Show Source):
You can put this solution on YOUR website! 53,477,4293,38637,347733
Take to the 4th differences to get them all the same
Assume a 4th degree polynomial
Substitute n=1,2,3,4,5 and solve the resulting 5x5 system
of equations:
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2,5,10,17,26,
Easy. That's 1 more than the sequence of squares 1,4,9,16.25
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-2,-8,-18,-32,-50
Easy. That's -2 times the sequence of squares 1,4,9,16.25
Edwin
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