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Edexcel A2 C4 Mathematics June 2015 - Official Thread

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Original post by iceangel8
Honestly thank you so much that is very helpful that's exactly what I needed! Good luck on Tuesday :smile:

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You're welcome. :smile: if a question like that comes up again, the main thing will probably spotting the right x value but it shouldn't take too much work. Luckily I sat C4 last year, but good luck to you too :smile:
When writing the integral with ln is it essential to use the modulus sign around the x within the ln?
Original post by joanneeve
When writing the integral with ln is it essential to use the modulus sign around the x within the ln?


I'd also like to ask this, I have no idea when to use modulus and when to use normal brackets with ln.
Original post by NikolaT
I'd also like to ask this, I have no idea when to use modulus and when to use normal brackets with ln.


You always have to use the modulus signs and then you can remove them if the question indicates they are not required.
Can someone please explain to me what part b) is actually asking for?

Does anyone have the link to the C4 IYGB papers/
Original post by joanneeve
When writing the integral with ln is it essential to use the modulus sign around the x within the ln?


I don't think it's essential to put in working for every question. But, there are certain questions where you may get a negative value inside the ln(x), so then you'd need to use the modulus signs to indicate your working. Otherwise, I think it's fine. I've never been marked down for excluding them.
Original post by RobHunter97
Can someone please explain to me what part b) is actually asking for?



You just multiply f(theta) by theta

f(theta) is shown in part a, so theta x f(theta) would be (1/2)theta + (7/2)thetacos2theta
Original post by dominicwild
I don't think it's essential to put in working for every question. But, there are certain questions where you may get a negative value inside the ln(x), so then you'd need to use the modulus signs to indicate your working. Otherwise, I think it's fine. I've never been marked down for excluding them.


okay thankyou! i just automatically do normal brackets so i just want to check i wouldnt loose marks :smile:
Original post by nayilgervinho
Does anyone have the link to the C4 IYGB papers/


http://www.thestudentroom.co.uk/showthread.php?t=3361905
Original post by joanneeve
When writing the integral with ln is it essential to use the modulus sign around the x within the ln?


only if there is a chance x may be negative.
Hi quick Q
The dy/dx of -2xy
I understand the product rule is applied. But I don't take minus out or do I ?
Ie -(2x dy/dx +2y) which would mean both become negative
OR
-2x dy/dx + 4y which leaves just x negative

Thanks
Original post by kaya_lioness
Hi quick Q
The dy/dx of -2xy
I understand the product rule is applied. But I don't take minus out or do I ?
Ie -(2x dy/dx +2y) which would mean both become negative
OR
-2x dy/dx + 4y which leaves just x negative

Thanks


take the minus out i would say then use the bracket so theres no confusion of signs
Original post by TeeEm
no worries

read instructions and all about difficulty rating in
http://madasmaths.com/archive_iygb_practice_papers_c4_practice_papers.html


Thank you!!


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Original post by Medicjug
TeeEm can you link me to some of your questions involving volumes of revolution questions where you have a line and a curve and you use the formula of a cone. I don't know if I am making any sense :smile: thanks


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there are some at this link .
http://madasmaths.com/archive/maths_booklets/standard_topics/integration/integration_volume_of_revolution.pdf
..
sorry I cannot give you question number because I am teaching at the moment
Reply 1215
What's the hardest c4 paper to date?
Original post by anonwinner
You just multiply f(theta) by theta

f(theta) is shown in part a, so theta x f(theta) would be (1/2)theta + (7/2)thetacos2theta


Thanks, I gave it a go but couldn't get it. Does anyone have a worked example, the mark scheme isn't making much sense to me

The rest of that paper (June 2010) was lovely though, some quite fun questions in there. That question would have been all I dropped marks on
Original post by RobHunter97
Thanks, I gave it a go but couldn't get it. Does anyone have a worked example, the mark scheme isn't making much sense to me

The rest of that paper (June 2010) was lovely though, some quite fun questions in there. That question would have been all I dropped marks on


Here you go https://www.youtube.com/watch?v=rs9Fq7CUs8U
My stomach is so quaky at the thought of this exam, it makes C3 look like a puppy. I think I have full UMS in C3 and if this one costs me the A* after that I will rip my hair out

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