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# Edexcel A2 C4 Mathematics June 2015 - Official Thread watch

1. (Original post by Paublo)
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.
Same
2. (Original post by maj156)
no it isn't
I think they were trolling
3. (Original post by abigail love)
but if you put 0.473 back into the original equation, you get a population 4000 so it's not 27 years sorry to disappoint :l
Incorrect logic, I am afraid.
If you put 27.3 back in the equation and used degrees to work out cos2t, you will still get 4000!
4. Am i the only one that literally had not enough time tofinish the paper.....ended up misses nost part b/c
5. (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?
That wasn't what you had to integrate. It was (3^x) ^2, which is not (9)^(x^2) but 3^2x.

EDIT: Beaten to it.
6. (Original post by jf1994)
Is this the same for if you're doing further pure maths?

So if I got 90% avg in C3 and C4 but totally flopped in FP2, but still managed to get 80% overall over C1 C2 FP1 and FP2 would I still get the A*?
They're two different A levels.

For an A star in maths you need 480 UMS and 90% avg in C3 and C4.

For an A star in FM, you need 480 UMS and 90% Avg in 3 of your A2 further maths modules. This can include a combination of FP2 or FP3 or Applied modules with a number 2 or above in their name.

What you get in FP2 doesnt not affect your 'normal maths' grade, only your FM
7. Anyone else get 54pi/ln3 for the last question?
8. on Q8 I forgot how to differentiate 3^x, so i rearrange y = 3^x to lny = xln3,so when differentiated i got dy/dx = xy/3 so dy/dx = 6, which gave me the tangent line y = 6x -3, which looked right on the diagram. I dont understand how this made me get such different answers as no logs included. Please can someone tell me if/what i have done wrong and if i would still get any method marks?
9. (Original post by Paublo)
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.
i agree with you on all of these
10. What was the partial fractions question? Was it P(P-2) or P(P-1) in the denominator?
11. Will I lose marks if I went to x^3 on binomal
12. (Original post by Ripper Phoenix)
radius of cone was 9-that point you 2-1/ln3
Yeah I used the x value instead of the y value. what an annoying mistake. how many marks do you think I'd lose? (I got the volume of the main function correct)
13. Hey guys, do I have to get 90 UMS or above in BOTH c3 and c4 to get an A*, or 90 UMS or above in average of c3 and c4?
14. (Original post by sat_freak)
Inorrect logic, i am afraid.
If you put 27.3 back in the equation and used degrees to work out cos2t in degrees you will get 4000!
if it works both ways then i'm sure you'll get some marks. but come on, given the initial conditions, if t=0 & P=3000, then what in another years 27.3 years the populations going to increase by 1000?! seems silly tbh.
15. (Original post by mrno1324)
Same
hi five
16. (Original post by Ripper Phoenix)
this is absolutely wrong!
I sincerely doubt it, for my final answer, 13π/ln(3) is correct. Please check your mathematical understanding prior to making abrupt swaying statements.
17. (Original post by RH0909)
Hey guys, do I have to get 90 UMS or above in BOTH c3 and c4 to get an A*, or 90 UMS or above in average of c3 and c4?
Average. 100 in C3 and 80 in C4 would suffice.
18. (Original post by rachelc142)
p was in thousands so you had to put p=4 in! I did this too then realised !

Posted from TSR Mobile
I only realised this seconds from the end but I did manage to put it into my calculator just in time. So I have put literally no correct working but did write the right answer - not sure how many marks that gets.
19. (Original post by C++)
Or simply let 3^(2x) = (3^(2)^x) = 9^(x);

This then gives (1/ln(9) * 9^(x)) + C
I dont know what you've been smoking but that is no where near mathematically correct
20. (Original post by Paublo)
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.
Things are definitely looking up for me right now!

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