Official Edexcel C3 Discussion Thread

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ollie_91

Are you sure 45 is a solution, because i know if you express cot as cos/sin it's possible, but i think that'd be harsh because if you put 45 into the original equation you will get math error. After all you are finding solutions for that equation.

Yes the solutions include 45. Try using your brain instead of your calculator when checking your solutions.

If you sketch the graph of y=cot t, it crosses the t-axis at 90, i.e. it equals 0 when t = 90 (I chose t to avoid confusion between x and 2x).

Reply 1281

kosy91

loop45

where is the core 3 marks scheme 2010?????

page 33, from ARSEY

Reply 1282

tiny hobbit

kosy91

Stop Using The Calculator To Get Q8 You Use Your Pen And Pape And Do It!!!!!!!

Apologies for just repeating your comment, I've only just started reading this thread.

Reply 1283

tiny hobbit

Nast

I get your point, but Edexcel knew we were going to use calculators in this exam, and most people check their answers by plugging their answer back into the question to see if it is right. When I do that and my calculator tells me one thing but my logic tells me another, who should I trust.

Yourself. Calculators cannot do everything.

Reply 1284

tiny hobbit

jayeshshah

Does anybody have the edexcel C3 Question paper dated 20th january 2010?
Thanks

Ask your teachers, they will have the spare copies.

Reply 1285

tiny hobbit

craglyboy

I thought this exam was solid tbh, but i thought this was the last oppertunity to take this exam how come people ar eon about retakes?

The specification for the Maths exams hasn't changed for 2008 onwards (except for D1/2 and the FP modules) so the other modules just carry on, unlike most subjects.

Reply 1286

kosy91

tiny hobbit

Apologies for just repeating your comment, I've only just started reading this thread.

thats ok.....no probs!!

Reply 1287

crazedmonkey09

Chrisharb

i had the same problem with the tany=x question aswell, stupid exam board, is it possible that they may cite a problem with the question?

There are 25 other letters they could have used, they could have phrased it differently, they could have even separated it more clearly i.e instead of it being 4ii) which almost certainly links to 4i) they could have made it 4b.
I also started subbing it in and got a complete mess of an equation thanks to their dodgy wording. Why the hell was it worth 5 marks when its was just 3 parts of working! I just can't get my head around it, its as if 1 mark was for knowing c4 arctan differentiation and the other was for avoiding strong hints.

Reply 1288

tiny hobbit

crazedmonkey09

Usually Edexcel A level Maths uses a) b) etc. when the parts of a question are linked and (i) (ii) etc when they are not.

Reply 1289

crazedmonkey09

tiny hobbit

Usually Edexcel A level Maths uses a) b) etc. when the parts of a question are linked and (i) (ii) etc when they are not.

That makes no logical sense as i is used to partition a and b questions just as a and b is used to partition 1 and 2.

Reply 1290

tiny hobbit

crazedmonkey09

That makes no logical sense as i is used to partition a and b questions just as a and b is used to partition 1 and 2.

Very true, but that is the general plan with the "first" partition.

Reply 1291

Arsey

crazedmonkey09

are you saying you put x = tany into your answers to part i)?

If so I understand what you mean but I can not see why anyone would have done that; anyway it should have been imediately obvious that doing that was never going to lead to the solution stated. Also, had the question expected you to do that it would have begun...

hence or otherwise.

I really don't see the problem with the question.

Reply 1292

crazedmonkey09

Arsey

Under the pressure of an exam things look very different, there were many things that made me think to do that, the unusually high marks for it - it must be complex which it certainly wasn't differentiate tan, use identity, dy/dx = 1/dx/dy i'm counting 3 steps there

Certainly in the way they used x and y again suggests replace this with this.
If it didn't say 'given that' there wouldn't be a problem.

Reply 1293

Pheylan

to the people who got confused by the "given that" in part ii) - what the hell did you make of the "given that" in part i) then?

Reply 1294

Chrisharb

crazedmonkey09

totally agree, they could of even written the equation above the part ii) to show that they were seperate, quite alot of people ~70% i spoke to post exam had an issue with this question

Reply 1295

Noble.

Chrisharb

totally agree, they could of even written the equation above the part ii) to show that they were seperate, quite alot of people ~70% i spoke to post exam had an issue with this question

0% of the people I spoke to had an issue with that question.

Reply 1296

crazedmonkey09

Chrisharb

totally agree, they could of even written the equation above the part ii) to show that they were seperate, quite alot of people ~70% i spoke to post exam had an issue with this question

Yeah, my class found this paper super hard apart from the ones who do further maths, and even they found it tricky. In hindsight it looks easy :mad:

It seems most people struggled with q4ii, the 7 mark trig and 9c that range one, maybe also find a and b (also trig). I'm just so frustrated that i could have gotten 90+ums in this, but i dropped about 11 marks through that question and stupid mistakes