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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 1platinum
I think 6 marks will be just for the differentiation and then 2 answer marks for the co-ordinates. Possibly 1 mark for the x co-ordinates and one mark for the y co-ordinates as the two answer marks.


Ah yeah, that sounds quite logical...thanks :smile:
Original post by sunnybacon
Ah yeah, that sounds quite logical...thanks :smile:


Do you know how to do the vectors 6 marker?
Original post by 1platinum
Do you know how to do the vectors 6 marker?


A link to my answer was put in the first post. :smile:
Reply 1003
Original post by 1platinum
Do you know how to do the vectors 6 marker?


The previous question (1 mark I think) told you what the length of the side was, then you needed to use the distance between two points formula (the point B should have been in terms of u), which gave a quadratic which I divided through by 5.
Reply 1004
for the part of question 5 when it asked about the normal, it only asked for the gradient of the normal so you didn't actually have to figure out the equation
Reply 1005
for the vector question,
for 7a I remember that it was something like P = (6,-2,1), may be wrong though
and the other part of the question was find AP^2 and I got it equal to 20.
then you use that value to find B and you get this once you've expanded all brackets:
20 = 45μ^2 + 90μ +45
so then: 45μ^2 + 90μ +25 = 0
then divide by 5: 9μ^2 + 18μ + 5 = 0
factorises to: (3μ +1)(3μ+5)
so then the values for μ are -1/3 and -5/3
then you subbed those back into the general coordinates for B
:smile:
Original post by 1platinum
Do you know how to do the vectors 6 marker?


Yeah, I just ran out of time unfortunately :frown:
I reckon I've dropped 8 marks altogether (the 6 from that question and max 2 from that implicit differentiation one)...I don't think the A* boundary will be as high as 67 so it should be alright, fingers crossed :tongue:
Reply 1007
Original post by lrbailey
for the vector question,
for 7a I remember that it was something like P = (6,-2,1), may be wrong though
and the other part of the question was find AP^2 and I got it equal to 20.
then you use that value to find B and you get this once you've expanded all brackets:
20 = 45μ^2 + 90μ +45
so then: 45μ^2 + 90μ +25 = 0
then divide by 5: 9μ^2 + 18μ + 5 = 0
factorises to: (3μ +1)(3μ+5)
so then the values for μ are -1/3 and -5/3
then you subbed those back into the general coordinates for B
:smile:


Yeah that's what I did. Quite a nice question apart from the horrible coordinates at the end. Hopefully no slips in working there.
Think I've got a raw mark of about 50. Lmao. Absolutely awful mistakes and time was dreadful. After getting 95 in C3 it's just ****ed me over. Wasn't difficult, just broke under the pressure.
Original post by Dangerous Theory
Was it exactly the same tho? And did you get 32.4 after? Cus it's not adding up, yet I swear I got that answer


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I seem to recall the second term being negative. Getting very concerned because I got 32.4 (well, 32.37... which rounds) but if I got my equation wrong and fluked the last part then bye-bye 10 marks, which I really need since I think I only got 49-55 and really need an A in this paper :/

EDIT: Yup, the second term is minus. Here is the wolfram-alpha link (all the x terms replaced with 2's, which required many brackets :/) - http://www.wolframalpha.com/input/?i=%28%285*2%29%28%282*2%29-1%29%5E1.5%29-%28%28%282*2%29-1%29%5E%282.5%29%29-4
(edited 11 years ago)
Reply 1010
Original post by mark17188
... just broke under the pressure.


I'm sure you're not the only one. I know a lot of others, capable of A*'s who were distraught after the exam (due to the mistakes exam pressure can cause).
I think it's seeing the massive mark questions that really makes you panic. When they're split it up it psychologically makes it seem easier.
Original post by VQG
This is what happened to me.. I completely broke down under pressure today. First time that's ever happened to me. I only needed 34 UMS for an A and I'm not sure if I've got that. I completely broke down in the exam for some reason, the questions looked much harder than when I looked at the paper at home. Maybe it's because I knew it was my last shot no retakes - but even then I had my last Chemistry exam yesterday and I felt okay in that. I went into the exam thinking no pressure I'll get 34 marks, but as soon as I sat down I panicked.


Yeh exactly what I get. Just constantly think of how it's your last chance.
Don't worry, I'm sure you've done fine. :smile: Just don't worry about it, nothing you can do about it now.
Reply 1013
Original post by f1mad
I meant to write h (I did in the real exam).

Just realised 'x' was required in part b) :lol:.


lol atleast you wrote h in the exam i ended up writing dh/dt = k(2-x) im so dumb no mark there :frown:
Reply 1014
was this question 8:
math 001.jpg
Original post by ghobro
was this question 8:
math 001.jpg


no it was 15
Original post by In One Ear
Lol my first reaction was *use IBP!* but i must admit i looked at it and thought no ****ing way will it work- obviously i must have been having my own retarded moment given that it seems the favoured method by a long shot. Substitution did indeed make it a very easy integral (probs a 5 marker in c3 if they told you to use it) meaning 8 marks overall (including eliminating the constant of integration) seemed generous using a substitution.


what the **** is IBP?
Original post by DavidMRoper
what the **** is IBP?


integration by parts- he started using the abbreviation so i just continued :smile:.
Reply 1018
Original post by mark17188
Think I've got a raw mark of about 50. Lmao. Absolutely awful mistakes and time was dreadful. After getting 95 in C3 it's just ****ed me over. Wasn't difficult, just broke under the pressure.


This. Made terrible mistakes which I don't usually make, didn't notice basic things. Just messed up completely... Only needed a C to get an A overall but even that's looking unlikely...
Original post by mojopin1
Yeah that's what I did. Quite a nice question apart from the horrible coordinates at the end. Hopefully no slips in working there.


Horrible co-ordinates convinced me that my answer was wrong, but from what I've seen on here, my working seems to have been right.

I have an irrational fear of 'ugly' answers, which is ridiculous at A-Level. I must admit that I looked at my A=4 for the constant on the last question and actually thought... "hmm... nice round integer - looks about right!" :P

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