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# MAT 2009 q1H watch

1. I feel like I'm almost there, but have done something wrong!
Question:

My working so far:Attachment 473229473231

Thanks
Attached Images

2. (Original post by IMZL)
...
n=N-1
3. Spoiler:
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Unless I've slipped up, this falls very quickly if you simply check the case N=1
4. (Original post by ghostwalker)
n=N-1
Ahhhh. How come though? I thought it'd be N-2 because the geometric series doesn't include 2 subordinates, namely y0 and yN(i.e. The values 1 and 2). Why is it N-1?
Thanks
5. (Original post by DFranklin)
Spoiler:
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Unless I've slipped up, this falls very quickly if you simply check the case N=1
Oh yeah, right you are. There's always some neat way that I never spot..
Thanks!
6. (Original post by IMZL)
Ahhhh. How come though? I thought it'd be N-2 because the geometric series doesn't include 2 subordinates, namely y0 and yN(i.e. The values 1 and 2). Why is it N-1?
Thanks
This is an off by one error. (Often called a "fence post" error).

When you have a sum , the number of terms is n+1-m, not n-m. (Try it for small m, n and you'll see).
7. (Original post by DFranklin)
This is an off by one error. (Often called a "fence post" error).

When you have a sum , the number of terms is n+1-m, not n-m. (Try it for small m, n and you'll see).
(idk why the latex isn't working but just pretend the m and n = 0 are in the correct places)

This would have m+1 terms right?
8. (Original post by Louisb19)
(idk why the latex isn't working but just pretend the m and n = 0 are in the correct places)
You need "\displaystyle" before everything to get the super big type which puts the limits in the correct place; does nice integrals too.

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