Finding the formula for a sequence
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Finding the formula for a sequence

[From: ] [author: ] [Date: 13-02-03] [Hit: ]
8,11,14,17 .........
I'm terrible at maths and I need some help with my homework.

(work out how many we add each time) > __ n+ __ < (work out what we add or take away from this to get the first term)

Question 1) 3,5,7,9,11 ...
Question 2) 5,8,11,14,17 ...
Question 3) 2,5,8,11,14 ...

So that's basically my whole homework sheet. What do I have to do? Can someone please explain it? It would be a big help!

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I'll tell you how to do it, so that it will help you in the future.
you need to work out the differernce between the numbers, so for:
question one the difference between the numbers is 2. So, you do 1 times 2 = 2, to get the first term, you need to add one, so the answer is 2n +1. To check this, pick say, the 4th number in the sequence, which is 9. 4 x 2 = 8. +1 =9, so this is right.
To find the fist part of the answer, (the _n part,) just picture it as time tables, and recognise what times table is used, and then what you need ot alter in that times table (adding or taking away)

_Answers_

1) 2n+1
2) 3n+2
3) 3n-1

Good luck with your hw!

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Question 1) add 2 each time to get the next number
Question 2) add 3 each time to get the next number
Question 3) add 3 each time to get the next number

I'll find a good website.

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The normal thing is to number the terms – we talk about the 1st term, the 2nd term, the 3rd term ... and eventually the "nth" term.

The magic of all this is that there are formulae to tell you what the nth term will be, and other formulae to tell you what the sum of all the terms up to a particular spot will be.

In Question 1) for instance, the nth term = 2n + 1

The 5th term, for argument's sake, is 2(5) + 1 = 11. We can see that this is true.

The 100th term (without having to count fingers & toes) = 2(100) + 1 = 201

It's all explained here: http://www.purplemath.com/modules/series…

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1) Add 2
2) Add 3
3) Add 3
1
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