Mr M's OCR (not OCR MEI) Core 2 Answers Thread May 2011

They ask for 3 sig figs so you'll probz lose an accuracy mark.

But isn't 6.50 to 3 sig figs anyhow? Or am I completely wrong?

Hey for the log question i didnt put 'x=' part but wrote the actual logarith. Is that alright
Sorry for all the qs lol.

I think half the people taking the exam have used degrees there - it may well be OK.

(1/6)pi is absolutely fine.

No as it was only one mark.

Mr M,

for quesion 2ii) I misread the co-ordinates (incredibly stupid I know :/ ) , and used 4, 7 instead of 4, 17, hence got the wrong value for c = 21, but method was perfect, how many marks out of 3 would I get?

Also, for question 8iii) I got the right answer, but I worked it out one way, then next to that, did it in another way to see if I was right, and for both it says x = log(base 2) 3 , there's no danger of losing marks there right?

Thanks a lot in advance!

2ii 2 marks

8iii no

drop 1 on each

What do you guess the grade boundaries to be for an A or B? Thanks.

really? only one mark despite not getting the trig function as tan and not getting 7pi/12

my working was

cos2x=root3sin2x then squared everything to get cos^22x=3sin^^22x
=> cos^22x=3-3cos^22x => 4cos^22x=3 => cos^22x=3/4
=>
cos2x = +/- (root3)/2 then got pi/12 and 5pi/12

so would that be enough for 3 marks or just 2 if that ? Thanks

drop 2 marks, one for failing to find the other two solutions and one for not rejecting two of them

thanks Mr M and question 9iii) i left it as x<= pi/6 and
x<=5pi/6

instead of pi/6<x<5pi/6

is that 1 or 2 marks lost ? thanks

Probably 1