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# Official Edexcel C3 Discussion Thread watch

1. (Original post by Kameo)
It could be M1 Jan 09 you needed 49 for an A, and I think this paper there was more areas to make mistakes. I think an A would be 50 something, it was much harder than past papers.
I found this paper in line with all the other past papers though I didn't think it was hard, some questions were tricky but it wasn't "hard"..idk.
2. for the ques with graph of ln|x|, would you reflect it in the y-axis and plots the -ve values as well (as stated in the unofficial mark scheme)??
a couple of my mates said it won't be reflected and just stay the same (ln x graph) 'cos ln x doesn't work with -ve x values??..

who's right??
3. (Original post by Superman_Jr)
No you wouldn't (no offence). I used a theorem I made called 'Supermans Theorem' which lets me calculate the grade boundaries, of course using very complicated numbers.....and err.....and yeah....dont know what I'm on...
I think it's bedtime for you, Superman Jr
4. (Original post by taherq)
Q7 Part C They Wanted The Answer To 3 Significant Figures But I Wrote It To 2 Significant Figures So Will I Lose Marks For That
you could lose an accuracy mark.
5. A invigilator put it on my desk
6. (Original post by tqpbuildingbonds)
for the ques with graph of ln|x|, would you reflect it in the y-axis and plots the -ve values as well (as stated in the unofficial mark scheme)??
a couple of my mates said it won't be reflected and just stay the same (ln x graph) 'cos ln x doesn't work with -ve x values??..

who's right??
Surely for that modulus graph you reflect everything in the positive x axis in the y axis.
7. for question 8 this is what i did:

first i wrote re-arranged cosec^2(2x)+cot2x-1=0

and said let u=2x

cosec^2u+cotu-1=0

then i used the fact, 1+cot^2(x)=cosec^2(x) subbed that into the equation

(1+cot^2(u))+cotu-1=0

cot^2(u)+cotu=0 >>>> cotu(cot2u+1)=0

cotu=0>>>1/tanu=0 or cot2u=-1 >>> 1/tan2u=0 DEADLOCK lol I stopped here l
8. (Original post by cashfield777)
After reading back a couple of pages, I might have lost marks on the last question as well for getting the range wrong on the last part... I actually can't remember what I wrote for it >_<

Also for question 4i) If I didn't simplify it fully (writing it as 2 fractions) will I lose many marks?
I didn't simplify it completely either. Hopefully we'll lose 1 mark AT MOST, maybe even none.
9. here's a little debate about the answer to the very last question to do with the range of the composite function. In general, when you inverse a function, its a transformation of the original function, thus it's original properties are transformed but still remain. But when you have a composite function, you are adding two different function together thus wouldn't it make new properties. Referring to the paper, the composite function fg(x) = x^2 - 2x + 4, which when differentiated gives a minimum turning point where fg(x) = 3, thus the range would fg(x) >= 3?
10. I don't think there's any point in predicting grade boundaries and stuff, it all depends on the national average of how well students performed overall (also some other factors) and nobody knows that (TSR does not account for the whole student population). You'll just be fooling yourself now just to find later you have done worse. Let's just wait and see...
11. (Original post by crazedmonkey09)
thanks i realise that now, i thought i was being so clever diffing it now i realise
do you reckon the statement assymtope at 0 q5 will be a mark? i damn well hope not, already lost a min 10 marks
no, it will not matter - it didn't ask for it. However, it should look like it isn't going to cross the axis on your diagram.
12. (Original post by hammerhasni5)
my mates who did it found it real easy.. but thats only cuz they had a friend from another school who finished the same exams half an hour earlier who gave them the questions!
Cheating *************!!!!
13. oh kewl...that's what i did...i was confused 'cos sum ppl (really clever!) in my class said it'll just be ln x graph...

bt i'm gonna take ur word on it
14. (Original post by Xtian)
I didn't simplify it completely either. Hopefully we'll lose 1 mark AT MOST, maybe even none.
Like you said, it would only be 1 mark at most. In past mark schemes I've seen full marks awarded for no simplification (further than collecting terms) so hopefully we'll be fine
15. (Original post by Xtian)
I didn't simplify it completely either. Hopefully we'll lose 1 mark AT MOST, maybe even none.
There was a similar question like that before, in the mark scheme they awarded full marks for the non simplified version.
16. how much marks would you lose if you have the correct answers but not to the correct accuracy for e.g they ask for 2 decimal places and you give four
17. I failed the funny thing is that my teacher decided to show us how arctanx differentiates into 1/root x^2+1 and we were like omg that was in the paper yesterday!
18. (Original post by MIKE ESSIEN IS QUITE SICK)
how much marks would you lose if you have the correct answers but not to the correct accuracy for e.g they ask for 2 decimal places and you give four
MIKE!!!!!!!!! hey mike!

I think 1 mark.
19. (Original post by shezarina)
i am such a retard, i didnt even do question 9 cos somehow i just didnt expect there to be anything after question 8. and that is the easiest thing i could've done.
cry
i hope the grade boundaries are loooow
or hello retake of everything.
one of my fellow homedogs encountered the same mishap. surely they will take this into account given the fact that the last 10 papers all only had 7/8 questions max
20. (Original post by h-star)
I failed the funny thing is that my teacher decided to show us how arctanx differentiates into 1/root x^2+1 and we were like omg that was in the paper yesterday!
A very similar question was in a past paper!

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