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FP1 Help

How do I get from
(p−q)x=2a(p−q)+a(p^3 −q^3) to x=a(p^2 +q^2 +pq+2)
I just can't see it, am I supposed to factorise (p^3-q^3) somehow?

Reply 1

username1560589

Original post by katie*may

How do I get from
(p−q)x=2a(p−q)+a(p^3 −q^3) to x=a(p^2 +q^2 +pq+2)
I just can't see it, am I supposed to factorise (p^3-q^3) somehow?

If you don't know the factorisation of

p^3 - q^3

, you should work it out. Guess one of the roots and so on.

note:

p^3 - q^3

is quite common. It's one of the factorisations that's useful to memorise(like difference of squares).

(edited 8 years ago)

Reply 2

MaySouth17

Original post by morgan8002

If you don't know the factorisation of

p^3 - q^3

, you should work it out. Guess one of the roots and so on.

note:

p^3 - q^3

is quite common. It's one of the factorisations that's useful to memorise(like difference of squares).

Ive tried doing that but I can't seem to get it, would you please tell me what it is?
I know it needs to have a (p-q) in it

Reply 3

MaySouth17

Oh i think I've done it-
is it (p-q)(p+q)(p+q)

Reply 4

Student403

Original post by katie*may

Oh i think I've done it-
is it (p-q)(p+q)(p+q)

Nope. (p-q)(p^2 + pq + q^2)

Reply 5

username1560589

Original post by katie*may

Ive tried doing that but I can't seem to get it, would you please tell me what it is?
I know it needs to have a (p-q) in it

Yes, it has (p-q) in it. I guess you've been taught how to divide polynomials by long division. So do

p-q ) \dfrac{}{p^3 - q^3}

Reply 6

MaySouth17

Original post by Student403

Nope. (p-q)(p^2 + pq + q^2)

Thankyou!! :adore:

Reply 7

Student403

Original post by katie*may

Thankyou!! :adore:

No worries :smile:

Which chapter is this from btw? Or topic I guess, if the exam board isn't Edexcel modular

Reply 8

MaySouth17

Original post by Student403

No worries :smile:

Which chapter is this from btw? Or topic I guess, if the exam board isn't Edexcel modular

Its Edexcel FP2 June 2007 Q8, its really an FP1 Q now though as they re organised the modules content in 2009 I think

Reply 9

Student403

Original post by katie*may

Its Edexcel FP2 June 2007 Q8, its really an FP1 Q now though as they re organised the modules content in 2009 I think

Oh okay. I'm starting FP2 in December. How difficult are you finding it?

Reply 10

MaySouth17

Original post by Student403

Oh okay. I'm starting FP2 in December. How difficult are you finding it?

Not too bad so far but we only started it last week haha

Reply 11

Student403

Original post by katie*may

Not too bad so far but we only started it last week haha

Lesson from every Edexcel module ever: Chapter 1 NEVER tells you the right difficulty lol

I did quite well on FP1, but everyone in the year above says FP2 is hard as hell. Quite nervous about starting it tbh

Reply 12

username1560589

Original post by Student403

I did quite well on FP1, but everyone in the year above says FP2 is hard as hell. Quite nervous about starting it tbh

I did AQA FP3, which I believe covers roughly the same content as Edexcel FP2. It's mostly an extension of C3-4, being calculus-based. I'd say it's a fair amount more difficult than C3-4, but very interesting.

Reply 13

Student403

Original post by morgan8002

Well that's great to hear! I heard yeah that the FPs are interesting modules. I loved FP1 so much

Reply 14

Zzzyax

the tricky thing here is factorising that p - q to the power 3 term for the division, which is simple and i think others have showed that, errrr otherwise its easy question