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# FP1 question ocr urgent -_- watch

1. Attachment 534779
Attachment 534779534781

how do you work out q 8 part iii) and also part iii) of the roots of polynomial question? (not the complex one)

I don't fully understand the markscheme. So if anyone could show the root of polynomial part iii) step by step that would be wonderful

For q 8...I got n/n-1 i believe ( i don't fully remember since I did it yesterday and i misplaced my working). But why is the answer 1- (n/n-1)?

Again workibg out would be extremely helpful. Thank you again!!
2. Can't see what the pictures are, what year is it so o can look it up

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3. I this off the January 2012 paper?

The 1 comes from n/(n+1) tending to 1 as n tends to infinity. The -n/(n+1) comes from the fact that the sum to infinity is missing the first n terms. From this you get -n/(n+1) as this part isn't being cancelled out by an earlier term. Therefore you get 1- n/(n-1)
4. (Original post by drandy76)
Can't see what the pictures are, what year is it so o can look it up

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It's paper june 2012 (ocr non mei). I apologise for the inconvenience! Something must have went wrong while attatching on my phone...

It is question 8 iii) and 6 part ii)
5. (Original post by jonnydowe)
I this off the January 2012 paper?

The 1 comes from n/(n+1) tending to 1 as n tends to infinity. The -n/(n+1) comes from the fact that the sum to infinity is missing the first n terms. From this you get -n/(n+1) as this part isn't being cancelled out by an earlier term. Therefore you get 1- n/(n-1)
Oh I see thank you! It's the june 2012 paper ocr non mei. So when n tends to infinity the expression doesn't tend to 0 but 1? Just to confirm.
6. (Original post by JulieEdiz)
Oh I see thank you! It's the june 2012 paper ocr non mei. So when n tends to infinity the expression doesn't tend to 0 but 1? Just to confirm.
Yeah. Because at infinite the difference between n and n+1 is basically zero. Hence you get n/n which = 1
7. my working out for them

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8. Should be noted that you can also use the equation from part i) to obtain 8/5 directly

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9. (Original post by jonnydowe)
Yeah. Because at infinite the difference between n and n+1 is basically zero. Hence you get n/n which = 1
Sorry it is late but i just wanted to ask..

sum of infinity from n+1= sum to infinity from 1 - sum from 1 to n...

Therefore why isn't it 0- n/n+1...

I understood what you said but it just doesn't make sense it i look at it from this point of view...
10. (Original post by JulieEdiz)
Sorry it is late but i just wanted to ask..

sum of infinity from n+1= sum to infinity from 1 - sum from 1 to n...

Therefore why isn't it 0- n/n+1...

I understood what you said but it just doesn't make sense it i look at it from this point of view...
Sum to infinity from n+1 is all terms from n+1 to infinity, i.e. n+1, n+2, n+3

Sum to infinity from 1 is 1, 2, 3, 4,5 etc including n+1 to infinity terms as they are inside of this region

sum from 1 to n is all terms 1,2,3,4,5 to n-1, and n.

so, from n+1 to infinity is sum from infinity from 1 minus the terms from 1 to n which you don't want, as you only want between n+1 and infinity

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