Official C3 Exam Discussion WJEC - 24/05/13

Oh statistics as well, hopefully another A*!

Aah that's great

anyone know on the part when they asked to show b=-2a then it asked find a and b
Any of you reckon it's two marks for each part since it was out of 4 marks also when it asked to prove the statement is false, was u ment to use a pos value as a and a neg value for b??

Can you guess grade boundaries for it?

If you’re looking for the A* boundary, then it’ll be 67/68 as the other person has said. That is a boundary that I would be most confident in predicting (it has been 67/68 for each of the last three papers, despite boundaries for an A varying by as much as three marks across those same papers).

Generally, C3 has lower boundaries for an A in June than January. January 2013 wasn’t difficult, and by looking the examiner’s report, there was only two part-questions that caused trouble for a large number of students.

For this paper, I think 3) b) will have caused a few problems, as well as 7). Many people on here have found the functions questions to be difficult, so I think most other students will have dropped marks on those. Some weaker students won’t have seen the simplification in 5) or even managed 2) b), and things like that. And perhaps even having a negative sign in the iteration question would have caused some careless student to lose marks...

I don’t think 1) b) is going to affect anybody other than the weakest students, especially as power rule has come up before.

I'm sure you'll done well though, and will be in and around the A*. Just focus on C4 now!

anyone know on the part when they asked to show b=-2a then it asked find a and b
Any of you reckon it's two marks for each part since it was out of 4 marks also when it asked to prove the statement is false, was u ment to use a pos value as a and a neg value for b??

yeah it would have been 2 marks for each and you just had to choose a value for both a and b (not sure about it being negative or positive, shouldnt matter though) and substitute it into the equation showing that they weren't equal therefore false.

It's two marks for showing that b = -2a, and then two marks for the values of a and b.

It doesn't matter which way around you do it (i.e. which is negative and which is positive), but you were meant to have a positive and negative value for a and b.



What did you actually do for the modulus question to show it was false? Did you just assign a positive value to a and to b, and then plug them into the equation to show they aren't equal? If so, then that is incorrect.

Yeah I think I did that :/ Kinda through me off guard when I saw that, wasn't expecting it! I would have loved to get an A* but I'll be really happy with an A Just gotta focus on mechanics and C4 now!

Yeah, it should have been something like...

Let a = 4, b = -6

LHS: | 4 + 1 | = | 5 | = 5

RHS: | (-6) + 1 | = | -5 | = 5

∴ LHS = RHS, but a ≠ b

∴ FALSE

Good luck with mechanics and C4! If you need any help with those modules, then please do let me know!

Aww right now I see! :/ how many marks was it out of? I hope no more than 3 or 4!
Aw thanks I'm gonna need all the luck I can get! Haha I need help with centre of mass and those beam things in M1 and all of M2
Thank you though, good luck with your revision too

It was only worth two marks, and I don't think you'll be alone in not having managed to answer it correctly. Far from it.

This: http://www.thestudentroom.co.uk/showthread.php?t=1632251&page=2&p=41142877#post41142877

Mainly the tips and formulae sheets for M1/M2/C4.

If you want to PM me for anything specific, then please feel free. Happy to help!