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AQA Core 4 Exam Discussion 14/06/2012 !Poll, paper and unofficial MS (first post)!

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Original post by f1mad
D2 :tongue:.

Good luck!

Sounds good :smile:.


Oh fun :P good luck as well! :smile:
Question 5.

ai)
Unparseable latex formula:

x = 2cos\theta y = 3sin2\theta[br]\[br]\dfrac{dy}{d\theta} = 6cos2\theta, \dfrac{dx}{d\theta} = -2sin\theta[br]\[br]\Rightarrow \dfrac{dy}{dx} = \dfrac{6cos2\theta}{-2sin\theta}[br]\[br]\Rightarrow Using\ cos2\theta = 1 - 2sin^2 \theta[br]\[br]\Rightarrow \dfrac{dy}{dx} = \dfrac{6 - 12sin^2 \theta}{-2sin\theta}[br]\[br]\Rightarrow \dfrac{dy}{dx} = 6sin\theta - 3cosec\theta



aii)
Unparseable latex formula:

m_{tangent}\ at\ \theta=\dfrac{\pi}{6} \Rightarrow sin\dfrac{\pi}{6} = \dfrac{1}{2}[br]\[br]m_{tangent} = -3 \Rightarrow m_{normal} = \dfrac{1}{3}



b)
Unparseable latex formula:

y^2 = 9sin^2 2\theta[br]\[br]Using\ sin2\theta = 2cos\theta sin\theta[br]\[br]\Rightarrow y^2 = 36cos^2 \theta sin^2 \theta[br]\[br]cos^2 \theta = \dfrac{x^2}{4}\ and\ sin^2 \theta = 1 - cos^2 \theta[br]\[br]\Rightarrow y^2 = \dfrac{9}{4}x^2 (4-x^2)

(edited 11 years ago)
Reply 862
Original post by LGrosvenor101
Oh fun :P good luck as well! :smile:


D2 is boring :frown: :tongue:.

Thanks! :biggrin:
Original post by SomeoneIveNeverMet
Ah look at us making silly mistakes :frown: sad times. I'm hoping it's no more than 1 or 2 marks (it was out of 6/7 marks I think, and that mistake was made on the very last line). Haha yeah I'm so so glad it was a nice vector question! Vectors were definitely my biggest worry.

What other subjects do you do?
Hmm, worst case, AAB, best case A*A*A ... other than that, I really can't tell :frown:
How about you? :smile:

I only have M2 left! :biggrin: you?


I know :frown: I'm hoping that I still got my nice A :L so I don't need to cling onto S2 so desperately :L and I've still got biology, chemistry, general studies and S2 to go! And i've already had 6 exams :frown: and oh, well at least thats good!

Its annoying because I think I'm on the ABB/AAB boundary :/ I still only need BBB to go to Birmingham though, which is handy! :biggrin:
Reply 864
Original post by lollyage
what were the grade boundaries last june?


a* - 58
a - 51
b - 46
c - 41
d - 36
e - 31
Overall, it didn't go as well as I'd hoped (due to stupid mistakes mainly, like square rooting and not taking a negative root). Ah well, should still get an A* overall so :s-smilie:
Question 6.

Unparseable latex formula:

9x^2 - 6xy + 4y^2 = 3[br]\[br]implicit\ differentiation[br]\[br]18x - 6y -6x\dfrac{dy}{dx} + 8y\dfrac{dy}{dx} = 0[br]\[br]\Rightarrow \dfrac{dy}{dx} = \dfrac{6(3x-y)}{8y-6x}[br]\[br]\Stationary\ at \dfrac{dy}{dx} =0[br]\[br]3x-y = 0 \Rightarrow y = 3x[br]\[br]\Sub\ this\ into\ original\ equation[br]\[br]27x^2 = 3 \Rightarrow x = \dfrac{-1}{3}\ or \dfrac{1}{3} \Rightarrow y = 1\ or -1

(edited 11 years ago)
I'll do the rest when I get home. :smile: What do people think so far about the answers?
Original post by Cath-ay
a* - 58
a - 51
b - 46
c - 41
d - 36
e - 31


Oh wow, praying for this again then!
Original post by Oromis263
Question 1.
ai)
Unparseable latex formula:

\dfrac{5x-6}{x(x-3)} = \dfrac{A}{x} + \dfrac{B}{x-3}[br]\[br]5x-6 = A(x-3) + Bx[br]\[br]Let x = 3 \Rightarrow 9 = 3B \Rightarrow B = 3[br]\[br]Let x = 0 \Rightarrow -6 = -3A \Rightarrow A = 2[br]\[br]\dfrac{5x-6}{x(x-3)} = \dfrac{2}{x} + \dfrac{3}{x-3}[br]



aii) 2lnx+3ln(x3)+c2lnx + 3ln(x-3) + c

bi)
Unparseable latex formula:

4x^3 +5x -2 = (2x+1)(2x^2 +px + q) + r[br]\[br]Using\ factor\ theorem,\ do\ f(\dfrac{-1}{2})[br]\[br]4(\dfrac{-1}{2})^3 + 5\dfrac{-1}{2} -2 = -5,\ therefore\ r = -5[br]\ [br]Now,\ 4x^3 +5x +3 = (2x+1)(2x^2 +px + q),\ so\ by\ inspection\ p = -1 and q = 3



bii)
Unparseable latex formula:

Now\ divide\ the\ function\ previously\ found[br]\[br]\Rightarrow \dfrac{2}{3}x^3 -\dfrac{1}{2}x^2 + 3x -\dfrac{5}{2} ln(2x+1) + c





I know I've got hardly any marks on this paper but I stupidly crossed out my working using the factor theorem! I got r=-5 as well :cry2:
Reply 870
can someone show how they got the answer for the vector question please :smile:
Original post by LGrosvenor101
I know :frown: I'm hoping that I still got my nice A :L so I don't need to cling onto S2 so desperately :L and I've still got biology, chemistry, general studies and S2 to go! And i've already had 6 exams :frown: and oh, well at least thats good!

Its annoying because I think I'm on the ABB/AAB boundary :/ I still only need BBB to go to Birmingham though, which is handy! :biggrin:


Don't worry, I'm sure you've got it, just work hard for S2 now :smile:
Ah that sucks :frown: when do you finish then? (And get off TSR and revise! :tongue:)

Birmingham is good, like Warwick :biggrin: I'm sure you'll be able to get the AAB though.
My insurance is AAA :frown: (for the masters course, I also have an ABB offer for the bachelors course (thank goodness!)).
Original post by f1mad
D2 is boring :frown: :tongue:.

Thanks! :biggrin:


Done any D2 revish? I haven't touched it for ages. Soo cannot be arsed. It's incredibly dull. At least D1 was a little bit fun..


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Reply 873
Original post by rosie17
can someone show how they got the answer for the vector question please :smile:


You had to use the fact that the modulus of both sides were equal (isosceles triangle).
Reply 874
Original post by Oromis263
I'll do the rest when I get home. :smile: What do people think so far about the answers?


Thanks for putting the answers up! I think I got similar answers! :smile:
Reply 875
Original post by f1mad
You had to use the fact that the modulus of both sides were equal (isosceles triangle).


yeh i did that as AP=BP but everyone seems to have different answers what did you get ??
Original post by Oromis263
I'll do the rest when I get home. :smile: What do people think so far about the answers?


I replied to your binomial one. I disagree with your range


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Reply 877
Original post by rosie17
yeh i did that as AP=BP but everyone seems to have different answers what did you get ??


I got what someone else posted here.
Reply 878
Original post by Dangerous Theory
Done any D2 revish? I haven't touched it for ages. Soo cannot be arsed. It's incredibly dull. At least D1 was a little bit fun..


This was posted from The Student Room's iPhone/iPad App


Nope, done nothing. I'll have to basically re-learn it haha.
Original post by SomeoneIveNeverMet
Don't worry, I'm sure you've got it, just work hard for S2 now :smile:
Ah that sucks :frown: when do you finish then? (And get off TSR and revise! :tongue:)

Birmingham is good, like Warwick :biggrin: I'm sure you'll be able to get the AAB though.
My insurance is AAA :frown: (for the masters course, I also have an ABB offer for the bachelors course (thank goodness!)).



yeah :smile: well, I also did AS Further Maths this year, so luckily all my modules can swap around to give me the best possible A2 maths grade :biggrin: and I finish on the 22nd, with biology :frown: have an exam every day next week apart from wednesday D: although Monday is General Studies :frown: and I'm hoping I get AAB as well! I loved both Warwick and Birmingham, but I always think there is some kind of disappointment when you don't get into your firm :/ and thats lucky! Wheres your insurance at? :smile:

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