Edexcel Maths C3

What other modules do you still have to learn for June?
I've pretty much finished C4 but I really need to do lots of practise to get above 90 in it. And I still have M1 and D2.

I have C4 and M2 in maths!!
And physics and bio!!

Thank you for the PM, I did read it but forgot to reply

Did you notice the extra gem?

No problem!!
thanks for the rep!!
did you find it useful?

I keep coming across this kind of question in the C3 Elmwood Papers, but I haven't actually seen it come up in the actual Edexcel past papers. An example is:

Prove by contradiction that $x^2 + y^2 \not= 18$

I frantically searched the Edexcel textbook for something remotely similar and I didn't find anything like this. So do we need to learn how to do it - because I frankly suck at it.

Are the Elmwood papers aimed at Edexcel or other boards as well - that would explain why...

Elmwood papers are aimed at Edexcel (well, I believe they publish several different papers aimed at different boards, but I assume you have the Edexcel ones)

From Edexcel C3 Specification:


So, yeah, it would be best to know how to solve them (even if, like you say, they haven't come up before, and are probably unlikely to).

If it did come up, I don't know how complicated such a question would be; however, as there is barely anything about it in their endorsed textbook, I doubt it could be too difficult, as long as you know the basics of how each method of proof works. Disproof by counterexample is pretty self-explanatory, and for proof by contradiction all you'd really need to do is to assume the opposite and show it leads to a contradiction (I hope). I don't recall any contradiction in the textbook, but some disproof by counterexample was in there I believe, and it was a pretty basic question.

Specifically about the question you quoted: I assume there is more to it? As that statement as it stands clearly cannot be proved.

Thanks! You're amazing.

And as for the question - that's all that was given and it tells you to prove it by contradiction.
This is how the answer was given in the mark scheme. Its question number 1.
http://www.srepapmaxeeeerf.org/A%20Level/Maths/Edexcel/C3/Elmwood%20Papers/Elmwood%20H%20MS.pdf

Oh and also your specification is for the old one, here's the new one...
http://www.edexcel.com/migrationdocuments/GCE%20New%20GCE/spec-gce-mathematics.pdf

I can't find anything to do with proof on it - so I assume those proof questions are from the old spec, in which case !! I couldn't do them anyway lol.

Sorry, but the same thing is in that spec. (page 31, under preamble). But my points still stand, it shouldn't be anything too hard (especially not with those previous module scores o_O)

And ooh, the question is minus not plus -- that makes more sense. Still, looking at the answer it's still not that nice of a question. But thanks for that link, from it I got all the others and will probably do them sometime.

Edit: Correct me if I'm wrong, but I got the impression the specs of all but a few modules haven't changed much (if at all). This one looks much nicer though

I've got a bad feeling I'm going to go from getting 100 in C1 and C2 to epically failing C3 as it's pretty much the follow-up to all the bits I was worst at in C2

I've got a bad feeling I'm going to go from getting 100 in C1 and C2 to epically failing C3 as it's pretty much the follow-up to all the bits I was worst at in C2

The bits you were 'worst at' in C2 which you still aced?

You'll be fine.

Are you also doing A level maths this year?

Seriously, don't worry. If u aced c1 and c2 and got 100, i'm sure u'll pass c3. i'm doing it atm as well, and it doesnt seem that bad.