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# Sequences Help!!! watch

1. This is a two part question, can somebody please me work it out:
3. A sequence a1,a2,a3,....... is defined by
a1=3
an+1= 3an-5, n>1

A. Find the value of a2 and the value of a3
B. Calculate the value of
5
ar
r=1

2. It means that the first term in the sequence is , and each term after that is given by the formula . So to get the next term, you multiply the previous term by 3, and then subtract 5.

just means the second term, and so on.

means the sum of the first five terms.
3. But that would give me this:
a2= 3(3)-5=4
a3= 3(4)-5=7

That looks right but of you do a4:
a4= 3(7)-5=16

It all goes wrong there isn't a sequence anymore
4. (Original post by AveUgotaWkdSide)
a3= 3(4)-5=8
Well that's not right, is it?

What you get will be a sequence, even though the numbers won't go up by a fixed amount each time. Don't worry about that.

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