Edexcel A2 C4 Mathematics June 2015 - Official Thread

Is anyone else freaking out? Because I'm freaking out. C3 was alright for me, but even with high UMS on that, I could mess it all up with C4 :frown:

I'm getting in the low 90s at the moment, and with pressure of the exam hall, I'm bound to drop so many more marks :frown:

exact same position here

Reply 1461

Bustamove

19

Original post by Gilo98

i do the exact same - did this last year. Disappointment of realising you did bad has such a larger effect that joy of finding out you did well - and then there is the whole UMS guessing game

I agree....
especially when you get those smug people on TSR who ask obvious questions such as: "I got 70+ marks out of 75 in C3, is that a A?"

And then you find out how bad you did compared to everyone else on that thread... that is the most demotivating thing one can feel after an exam...

I'll try not to look at what I got after C4, but it's soo difficult not to......

(edited 8 years ago)

Reply 1462

Bustamove

19

How good are the gold papers in preparation for C4? I've done 2 today and plan to finish the other 2 by the end of today.... I've done all the papers from jan 2009 - june 14.... anyone got anymore suggestions to what other papers I should look at?
I probably have time for one more paper along with the 2 last gold papers that I'm planning to do.. wanna get a good sleep before tomorrow to reduce my chances of making stupid mistakes...

Reply 1463

WillGood

3

Original post by DanyaI

Does anyone have a list of all the trig identities and other formulas we need to remember for this paper? i.e. those not on the formula booklet

For Trigs i just learnt how to derive them rather that remeber them. Its pretty easy. I dont know them by head myself. I just derive.

Sin²A + Cos²A = 1 🅰
1 + cot²A = cosec²A (divide 🅰 by sin²A)
Tan²A + 1 = sec²A (divide 🅰 by cos²A)

Sin(A+A) = SinACosA + SinACosA
Therefore Sin(2A) = 2SinACosA
(This is from Sin(A+B) formulae)

Cos(A+A) = CosACosA - SinASinA
Therefore
Cos(2A) = Cos²A - Sin²A
= 1 - 2Sin²A
( rearange 🅰 make Cos²A the subject and replace)
= 2Cos²A - 1
(rearange 🅰 make Sin²A the subject and replace)

The rest should be at the back of the book.

(edited 8 years ago)

Reply 1464

nayilgervinho

7

I think it's a good thing I got in the high 90s for C3 because getting an 90 ums in C4 is ridiculously difficult.

Reply 1465

nayilgervinho

7

How is everyone feeling for tomorrow?

Reply 1466

rory58824

2

Original post by nayilgervinho

How is everyone feeling for tomorrow?

One word: integration.

Reply 1467

DanyaI

12

Original post by WillGood

For Trigs i just learnt how to derive them rather that remeber them. Its pretty easy. I dont know them by head myself. I just derive.

Sin²A + Cos²A = 1 🅰
1 + cot²A = cosec²A (divide 🅰 by sin²A)
Tan²A + 1 = sec²A (divide 🅰 by cos²A)

Sin(A+A) = SinACosA + SinACosA
Therefore Sin(2A) = 2SinACosA
(This is from Sin(A+B) formulae)

Cos(A+A) = CosACosA - SinASinA
Therefore
Cos(2A) = Cos²A - Sin²A
= 1 - 2Sin²A
( rearange 🅰 make Cos²A the subject and replace)
= 2Cos²A - 1
(rearange 🅰 make Sin²A the subject and replace)

The rest should be at the back of the book.

Great! Thanks a lot, the only two I struggle to remember are the cot^2 and tan^2 ones, so remembering how to derive them will be handy so thanks again :smile:

Reply 1468

Faded-Pi

3

Original post by Bustamove

How good are the gold papers in preparation for C4? I've done 2 today and plan to finish the other 2 by the end of today.... I've done all the papers from jan 2009 - june 14.... anyone got anymore suggestions to what other papers I should look at?
I probably have time for one more paper along with the 2 last gold papers that I'm planning to do.. wanna get a good sleep before tomorrow to reduce my chances of making stupid mistakes...

The Solomon papers?

Reply 1469

Kevin De Bruyne

21

Original post by nayilgervinho

Can someone help with 6a.
https://2f891307968364453c9a8f2316b1ff0e3451679f.googledrive.com/host/0B1ZiqBksUHNYVS11dkN0aVEybm8/Paper%20D%20QP%20-%20C4%20Elmwood.pdf

Find the turning point and use the graph.

Reply 1470

Thao Nguyen

1

(Using Cauchy's inequality)
y=x+9/x(divide both side by x because x>0 so does not affect)
x+9/x >= 2 root(x x 9/x)= 2root9=6 (a^2+b^2>=2ab from the fact that (a-b)^2>=0 with all values of a&b)
=>y>=6

Reply 1471

username1162972

18

Original post by Thao Nguyen

(Using Cauchy's inequality)
y=x+9/x(divide both side by x because x>0 so does not affect)
x+9/x >= 2 root(x x 9/x)= 2root9=6 (a^2+b^2>=2ab from the fact that (a-b)^2>=0 with all values of a&b)
=>y>=6

Use Chebysev's

Posted from TSR Mobile

Reply 1472

Raizel

3

sin3xcosx
how to go about integrating that?

Reply 1473

leerachelll

Hey guys, anyone knows what formulae we need to memorise in terms of the volume of a cylinder and stuff like that? Or would they give it to you in the question? Thanks!

Reply 1474

tiny hobbit

15

Original post by Bustamove

How good are the gold papers in preparation for C4? I've done 2 today and plan to finish the other 2 by the end of today.... I've done all the papers from jan 2009 - june 14.... anyone got anymore suggestions to what other papers I should look at?
I probably have time for one more paper along with the 2 last gold papers that I'm planning to do.. wanna get a good sleep before tomorrow to reduce my chances of making stupid mistakes...

Have you done the R papers for June 2013 and June 2014? Or the C4 questions from the IAL C34 papers? They're written by the same team as write the ordinary ones.