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# Edexcel A2 C4 Mathematics June 2015 - Official Thread Watch

1. (Original post by cogito.)
NO, if you use degrees you will get M0 A0 for final 2 marks because degree is not alternative method but the WRONG method.
2. What do you guys think Grade boundaries will be for an A*?
3. (Original post by Paraphilos)
I'm not sure you should have been having to integrate that in the first place in C4. Was there a previous part to the question?
whoops sorry think i got muddled. it was 3^2x. i must have gotten 9^x^2 from somewhere else. fml, i black out after such exams LOL.
4. (Original post by C++)
Or simply let 3^(2x) = (3^(2)^x) = 9^(x);

This then gives (1/ln(9) * 9^(x)) + C
this is absolutely wrong!
5. (Original post by talkbiology)
Rings a bell! for the volume of revolution I got 13pi / ln3, any confirmation?
i got that too! wasnt sure though because i intergrated by substitution
6. for the last question part b, I did the right method but when I went to work out my cone for h I did 9- x co ord of Q instead of 2 lmaooo what an idiot :-( how many marks do people think I could still get ?

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7. My answers for this paper were:
1) 2+5x/4-25x^2/64
3rt2/2
181/128
2)(2x-3y)/(3x+8y)=dy/dx
+-(24/5,16/5)
3)x=4ln(2)
12+32ln(2)^2-32ln(2)
4) A=5,1,3
p=15
31.82
d=7.46
5)27/32
a=2 b=-5
6)k=4
4pi/3 + rt(3)/2
7) 1/(p-2) - 1/p
0.473
8) x=2 - 1/ln3
area = 13pi/ln3
this is most of the questions that i wrote down my answers to, I am confident in most of them although I am prone to the occasional stupid mistake so if you disagree then I will not argue with you.
8. (Original post by mahatma ghandi)
its 473 years, it's in 100s of years bro
no it isn't
9. (Original post by JulianS96)
I got the same thing too.
Something like 12000 -6 = 4000e^1/2sin2t
Then ln2.9985 = 1/2sin2t
Therefor 2ln2.9985 = sin2t
Therefore 2t equals Math Error
P was population measured in thousands, so 4000 people meant P became 4
10. (Original post by PaulCJH)
My answers, judging by other people's opinions I think they're right:
Attachment 429779
Thank you so much! If these are right then the only one I got wrong was 7c), the DE populations one where I didn't realise it was in thousands -.-
11. (Original post by Bustamove)
with the 32ln(2)^2 -32ln(2) + 12, I simplified it even more to 64ln(2) - 32ln(2) +12... ended up getting 32ln(2) +12.... is that still correct or would I lose a mark?
(ln(2))^2 is not the same as ln(2^2) or 2ln(2)
12. (Original post by sagar448)
What do you guys think Grade boundaries will be for an A*?
69/70
13. (Original post by abigail love)
whoops sorry think i got muddled. it was 3^2x. i must have gotten 9^x^2 from somewhere else. fml, i black out after such exams LOL.
Ok. In that case, you make a substitution of in order to solve the integral.
14. How many marks for integrating correctly, finding volume of cone correctly, but manipulation error in between, leading to the wrong answer?
15. **** THIS. Im off to ecaudor on Thursday, so I can drown my sorrows there
16. (Original post by joanneeve)
anyone get 53pi/ ln3 for the last question?
its 13pi/ln3 sorry :c
17. (Original post by rachelc142)
for the last question part b, I did the right method but when I went to work out my cone for h I did 9- x co ord of Q instead of 2 lmaooo what an idiot :-( how many marks do people think I could still get ?

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None 😉

Probably 3 or 4
18. If I put 27.1 instead of 0.473 in question 7, I will lose only one mark right? I did put 0.473 as radian is default but then wonder why it is so short and changed it to degree . How sily I was

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19. such a hard exam I had no time
20. VOTE NOW ON HOW YOU FOUND THIS EXAM!
Note: C4 JUNE 2015 UK paper ONLY!

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