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Mr M's OCR (not OCR MEI) Core 2 Answers May 2012 <strong><font

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Mr M for 7ii I got positive the answer you put not negative
How many marks would I lose?
And for 5b I misread the first 9 for 19 :facepalm2: but did the rest ok how many marks would I lose there?
Thanks
(edited 11 years ago)
Reply 41
Original post by Mr M
none


yay!!!
Original post by Mr M
]ks)


hey how much do you think will be lost for Q4, i found 2 extra values... including the ones you've given, i hope it's just one..

also for 7B, i found 3 root 3 over 8, however i put this value into Siny to get 40 degrees something, would i still get all the marks.. ?

Thanks so much for the answers btw, really appreciate it.
Original post by matty b
what are the marks for on q's 9aii, 9bii , 8ii and 7aii? i know there's an answer mark, but what about the method marks?


the mark scheme hasn't been finalised yet so no-one knows
Reply 44
Original post by IShouldBeRevising_
Hey do you remember what the last question was by any chance, I mean the last part of the last question one that was worth 5 marks.


the questions are here

http://www.thestudentroom.co.uk/showthread.php?t=2003552&page=18
Original post by AKayaker
Hi Mr M
For the alpha beta question there was a cheat method on the calculator
For the alpha if you did (cos(tan-1(0.4)))^2 the calculator gave you 25/29 so you could just write down the answer as sqrt(25/29)
the same thing also worked for the beta question
This method meant I had hardly any workings, will I get all the marks for the answer, also will I lose marks as I think i forgot to change both down to surds (I left them as 5/sqrt(29) and -sqrt(40)/7 ) as it didn't say in the question it had to be simplified and I stupidly forgot


They are exact values so should be fine.
Reply 46
Messed up a bit, probably got somewhere in the high 50s, but could have done with high 60s really.
How come you couldn't have 270 for question 4?
Original post by jodiedoodles
pretty sure a was log (base 2) 27, r was log (base 2) y

It was definately those two, just can't quite remember which was around!


Yeah it was them thanks
Reply 48
Original post by JessLamb
why are these correct? i'm confused how you got those answers?


Q4) solve 4cos^2+7sinx-7=0, between 0 and 360

4(1 - (sinx)^2 ) + 7sinx - 7

= - 4sinx^2 + 7sinx - 3 = 0

4sinx^2 - 7sinx + 3 = 0

(4sinx - 3) (sinx - 1) = 0

therefore sinx = 3/4 and 1

sin^-1(3/4) = 48.6 and (180 - 48.6)

sin^-1(1) = 90

therefore, x = 48.6, 90 and 131.4
Original post by jodiedoodles
Mr M , for the last question I must have done something stupid somewhere as I worked out y = 6, and substituting this back in got -3 (we wanted 3) . I think I've just messed my signs up somewhere, but I'm pretty sure I done the same working as my friend who got the correct answer as 2/3 (I think?)

Would I still gain method marks, and lose the answer mark? How many marks do you estimate I would lose here?

Thanks!


Lose no more than 2 marks.
Original post by Mr M
They are exact values so should be fine.


Mr m I did not write 15 (CM) for the radius question I just wrote 15 will I still get the marks
Original post by sj_1995
If, foolishly, I did (3+2x)^5 - (3-2x)^5 instead of plus, would I get any marks? Im sure i read somewhere in an Old OCR mark scheme there was a mark for correct working put incorrect question copying!

Or am I dreaming....

Other than that really happy with the paper!


Just lose one mark if you did your calculation correctly.
Hi Mr M,

For question 4, I used the right trig identities and got to 4sin^2x - 7sinx + 3 = 0 (not sure if I've remembered it correctly) but then I must've stupidly factorised it wrong and ended up with x= 30, 150.

Do you think I'd get any of the 6 marks, seeing as my method was correct(ish)?

Thankyou!
Original post by halii_94
Mr M for 7ii I got positive the answer you put not negative
How many marks would I lose?
And for 5b I misread the first 9 for 19 :facepalm2: but did the rest ok how many marks would I lose there?
Thanks


Lose 1 mark

Lose only 1 mark if you are lucky
Original post by Mr M
Lose no more than 2 marks.


Thanks! Sorry to be a pain but do you have any idea how many raw marks around 75-80 UMS would need? :smile:
Original post by peachesandcream77
hey how much do you think will be lost for Q4, i found 2 extra values... including the ones you've given, i hope it's just one..

also for 7B, i found 3 root 3 over 8, however i put this value into Siny to get 40 degrees something, would i still get all the marks.. ?

Thanks so much for the answers btw, really appreciate it.


Just lose 1 mark and then get full marks
Reply 56
Hello Mr M,
If I wrote 2sqrt10/7 for 7(ii), how many marks will I lost?
On the last question I got y to equal -1 would I get any method marks or none at all?

This was posted from The Student Room's Android App on my HTC One X
Original post by Ursin
Messed up a bit, probably got somewhere in the high 50s, but could have done with high 60s really.
How come you couldn't have 270 for question 4?


It isn't a solution - I don't know where your 270 came from?
Original post by IShouldBeRevising_
Mr m I did not write 15 (CM) for the radius question I just wrote 15 will I still get the marks


The answer is 15. That's correct.

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