FP1 Tricky Series Question

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10 ii) I can't get the correct sereis expansion for n+1

Can anyone help me out please

Is it the 2n+1 bit you're referring to?

If so, then think how you can express the series of (2n+1), splitting them up as you do for the other two terms in the original sum may help.

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10 ii) I can't get the correct sereis expansion for n+1

Can anyone help me out please

https://7cba9babeb0db0ff9468853e0b2d0a80708ec59c.googledrive.com/host/0B1ZiqBksUHNYZGxseFBIQkphV0k/June%202013%20(R)%20QP%20-%20FP1%20Edexcel.pdf


10 ii) I can't get the correct sereis expansion for n+1

Can anyone help me out please

Thank you for your reply, I am still unsure with the expansion of 2n+1, why is the n here not being expanded to (n/2)(n+1). :?

Is (n+1) the last term it could be?

Enjoy and hope it helps!


Posted from TSR Mobile

Sorry, my post above is misleading and I see the (n+1) that you're talking about.

The series is in terms of r, which changes, but n is a fixed constant (very sneaky). So when r = 0, you add on 2n and 1, when r = 1 you add on 2n +1 as well as r^2 - 2r.

You would think it expands because it feels like it should be n=1, n=2 so you can sum it up, but it's always 'n' being added on.

Thank you both so much, this is incredibly helpful and I understand, prsom. Thank you for your detailed responses I really appreciate it

No worries! Good luck for your FP1 exam, if you need any help just message me.

Thank you so much, are you doing any maths a level exams

I am doing M2-3, S1-2, C3-4, FP1-3, STEP 1, AEA. All apart from last 2 are OCR


Posted from TSR Mobile

Impressive, I am doing FP1-FP2, C3-C4 M2 S2-S3

With Edexcel though.

Are STEP and AEA as difficult as everyone makes out?

STEP is certainly as difficult as it is made out to be however with rigorous practice over half a year you pick up trucks, strong algebra fluency and abilities which greatly aid you in the exam along with all other Maths exams. AEA is just a very very hard a level paper, I've only done 1 paper, will do a couple more in half term then do 10 or so in 3 days before the exam (it's my last one 4 days after my previous one). It isn't as hard in my opinion but it has high grade boundaries and many people don't take it seriously enough so don't do well. You can't afford to not answer any question in AEA whilst in step you pick 6 out of 13 so you can focus on strengths.


Posted from TSR Mobile

I see good luck with it all, I am sure you will be fine with it all though.

Sorry, my post above is misleading and I see the (n+1) that you're talking about.

The series is in terms of r, which changes, but n is a fixed constant (very sneaky). So when r = 0, you add on 2n and 1, when r = 1 you add on 2n +1 as well as r^2 - 2r.

You would think it expands because it feels like it should be n=1, n=2 so you can sum it up, but it's always 'n' being added on.

So if there's 3n^2 +2 we would add (3n^2 +2)(n+1) if it's from r=0?

What if it's from r=1?


Posted from TSR Mobile

Yes

If r = 1 then you have 1 less (3n^2 + 2).

So it would simply by (n)(3n^2 + 2)?


Posted from TSR Mobile

Edit: Misleading - see below.

Enjoy and hope it helps!


Posted from TSR Mobile