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    I feel like I'm almost there, but have done something wrong!
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    My working so far:Attachment 473229473231

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    (Original post by IMZL)
    ...
    n=N-1
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    Unless I've slipped up, this falls very quickly if you simply check the case N=1
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    (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?
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    (Original post by DFranklin)
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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..
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    (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?
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    This is an off by one error. (Often called a "fence post" error).

    When you have a sum a_m, a_{m+1}, a_{m+2},...,a_{n-1}, a_n, the number of terms is n+1-m, not n-m. (Try it for small m, n and you'll see).
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    (Original post by DFranklin)
    This is an off by one error. (Often called a "fence post" error).

    When you have a sum a_m, a_{m+1}, a_{m+2},...,a_{n-1}, a_n, the number of terms is n+1-m, not n-m. (Try it for small m, n and you'll see).
     $\sum_{n=0}^{m} ar^{n}$ (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?
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    (Original post by Louisb19)
     $\displaystyle\sum_{n=0}^{m} ar^{n}$ (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.

    \displaystyle\int_0^4
 
 
 
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