Recursive and Explicit Formulas for Sequence 1,-2,3,-4,5: Homework Help

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SUMMARY

The discussion focuses on deriving the recursive and explicit formulas for the sequence 1, -2, 3, -4, 5. The explicit formula is established as F(n) = ((-1)^(n+1)) * n. The recursive formula remains unresolved, with hints suggesting it may involve a relationship like F(n) = - (F(n-1) + 1), where the sign alternates based on whether n is odd or even. Participants emphasize the importance of manipulating expressions to express F(n+1) in terms of previous terms.

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Homework Statement



I need to find the recursive and explicit formulas for the sequence 1,-2, 3, -4, 5

Homework Equations



Recursive Rule: Fn= Fn-1 + Fn-2
Explicit Rule: position of terms F1, F2, F3,...

The Attempt at a Solution



I have figured out explicit because its ((-1)^n+1)n

Recursive rule i am having trouble with because its around something like -(Fn-1 +1) or close to that
 
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Let a(n) be nth term. You should be able to say what a(1) is. Now manipulate the expression for a(n+1) until you have a right side that depends of a(n), a(n-1), etc.
 
the sign of the added one will change depdneding on whether n is odd or even
 

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