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# AQA A2 Mathematics MPC3 Core 3 - Wednesday 15th June 2016 [Official Thread] watch

1. (Original post by ama1234a)
Can anyone tell me how to do June 2015 6c?

Also, in vector equations when you have to square the vector, why do we usually have to do that in a typical question? Whats the purpose of that?

Thank you
"Square the vector"? You can find the magnitude (or length) of the vector by squaring each component, adding them together and then square rooting it if that's what you mean (or Pythagorus, in other words)
2. (Original post by ama1234a)
Can anyone tell me how to do June 2015 6c?

Also, in vector equations when you have to square the vector, why do we usually have to do that in a typical question? Whats the purpose of that?

Thank you
The only time I have seen squaring the vector is when they asked for (AB)^2, which means the length of the vector (A->B) squared.
3. (Original post by bartbarrow)
"Square the vector"? You can find the magnitude (or length) of the vector by squaring each component, adding them together and then square rooting it if that's what you mean (or Pythagorus, in other words)
(Original post by Dapperblook22)
The only time I have seen squaring the vector is when they asked for (AB)^2, which means the length of the vector (A->B) squared.
I don't know which paper it was but I think I saw it once when they were asking for possible coordinates?
4. (Original post by C0balt)
I think I got everything right if I didn't make any silly mistakes.
But there was solid of revolution question which was a double parts thing and
x=1 to x=1/3
y=(ln3x)/x
For which I got something like pi (-(ln3x) ^2+2ln3+4) I can't remember exactly but it was ugly

Finding range we had to differentiate to get maximum point

Then we had to show secx+tanx=-0. 2 given that secx-tanx=-5, my friends had problem with it and it was 2 marks but I took half a page to work it out!
Dont you combine secx - tanx into a single fraction and use difference of two squares?
5. (Original post by jimgardner)
Dont you combine secx - tanx into a single fraction and use difference of two squares?
Well mine works and proves it anyway doesn't matter which method you use lol
6. (sec x - tan x) * (sec x + tan x) = sec^2 x - tan^2 x (difference of two squares) and this in turn is (tan^2 x + 1 - tan^2 x) = 1

Therefore sec x + tan x is simply the recipricol of sec x - tan x and therefore = 1/-5 = -0.2. The trick here is to spot the latter which gives you a clue to solving it
7. UMS prediction for 35-40 raw?
8. (Original post by hi-zen-berg)
UMS prediction for 35-40 raw?
If you're talking about the core 4 I would probably say a D so around 50 UMS
9. (Original post by hi-zen-berg)
UMS prediction for 35-40 raw?
10. (Original post by sean.17)
If you're talking about the core 4 I would probably say a D so around 50 UMS
Cheers; bur I meant for C3
11. Does anyone have Q6 for C4?

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12. (Original post by Examguy123)
This was the last time this spec would be done, instead of giving a nice easy exam they made it super hard
Not quite - the current AS students will have C3 / C4 next year, and there will be one more year of it after that. So there may be two papers even harder than this one...
13. Is there a 2016 C4 unofficial mark scheme anywhere. I cant find it.
14. As a further maths student and an Oxford offer holder I can confirm that was a fairly difficult paper, although I think I managed OK

I dropped at least 4 marks - At least 2 from Simpson's rule (It's 4*odds + 2*evens, right? I think I did it the wrong way around - regardless, my answer disagreed with my calculator, this thread, and Wolfram Alpha)

I then dropped at least one mark for the range question, I wrote 16ln8-8 when it sjould have been 8ln8-8.

Finally, I f*cked up gg(x) - I wrote gown g(x) = 1/x, but then I stupidly said gg(x) = 1/x^2 instead of just x
15. (Original post by umpa_dumpa)
Is there a 2016 C4 unofficial mark scheme anywhere. I cant find it.
At the moment the answers are just scattered across the C4 thread.
16. I might as well collect my answers together for reference:

1) p = -2

2) x2 = 2.366,
x3 = 2.054
∫5-x^x dx = 4.01 (This is wrong - Wolfram Alpha says 4.48609 -
https://www.wolframalpha.com/input/?...rom+0.5+to+1,7)
∫x^x = 1.99 (Also wrong, W.A. says 1.51391 -
https://www.wolframalpha.com/input/?...rom+0.5+to+1,7)
Probably method marks for subtracting previous answer from 5*(the interval)

3) x <= -6, 1 <= x <= 2, x >= 3

4) translate (5, 0), stretch s.f. 1/2 in x direction (Or stretch first then translate (2.5, 0)
n = 2, m = 3, or maybe other way around, can't remember which was which

5) f(x) <= 8ln8 - 8 (I got it wrong and said 16ln8-8)
gg(x) = x (I said 1/x^2)

6) 5pi - pi(ln3 + 1)^2 (which is equivalent to 4pi - 2pi*ln3 - pi(ln3)^2)

7) -√5

8) 117/224

9) cos x = -2/5.2, x = -21.3°(There was another value too, but plugging it back iinto the equation didn't give the result they asked for, so it had to be rejected)
17. is there an unofficial mark scheme?

18. yes, c was pi

I got the implicit differentiation right (2sec^x = 3x) and used sec^ = 1 + tan^2, but I got k=2 not 6. I got the integral in part b right, just had 1/2tan^-1(3x/2) and not 1/6. Would I get 2/3 on first and 7/7 on second for follow on marks?

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19. (Original post by Yo12345)
I got the implicit differentiation right (2sec^x = 3x) and used sec^ = 1 + tan^2, but I got k=2 not 6. I got the integral in part b right, just had 1/2tan^-1(3x/2) and not 1/6. Would I get 2/3 on first and 7/7 on second for follow on marks?

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For Q8

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20. ..

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