# need help on another C1 sequences question

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#1
The rth term of an arithmitic series is (2r-5)

a.) write down the first three terms of this sequence.
0
4 years ago
#2
oh my god a cat .....sorry i dont know
2
4 years ago
#3
So it would be 2 * 1 - 5 = -3

Second term, r=2

2 * 2 - 5 = -1

I'm sure you can work out the last one 😊
4
4 years ago
#4
(Original post by G-Rodge)
SO, the word arithmetic means that every term is squared. So first you have to square 2r-5(2r-5)^2 = 4r^2 -20r +25Then since that is the rth term and r is the 18th letter of the alphabet you sub in 18. Then multiply by 3 (since you want the first three terms) and split into any 3 (whole) numbers that add to make the number you get.Hope this Helps
Arithmetic means it's a constant progression sequence. That is it will increase or decrease by a constant amount.

-3 + -1 + 1 is an arithmetic sequence as you increase the previous term by +2
0
4 years ago
#5
(Original post by G-Rodge)
SO, the word arithmetic means that every term is squared. So first you have to square 2r-5

(2r-5)^2 = 4r^2 -20r +25

Then since that is the rth term and r is the 18th letter of the alphabet you sub in 18. Then multiply by 3 (since you want the first three terms) and split into any 3 (whole) numbers that add to make the number you get.

Hope this Helps
this is not the jokey forum. you want Chat.
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