Mr M's OCR (not OCR MEI) Core 2 Answers May 2012 <strong><font
Maths exam discussion - share revision tips in preparation for GCSE, A Level and other maths exams and discuss how they went afterwards.
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Re: Mr M's OCR (not OCR MEI) Core 2 Answers May 2012Thanks I realised that i misread -7 for -8 so factorised it wrong! Stupid mistake!(Original post by kenann)
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 -
Re: Mr M's OCR (not OCR MEI) Core 2 Answers May 2012Q3 drop 1 mark(Original post by hannah1994)
I stupidly didn't read the pi after the 45 in question 3, but did everything else right. How many marks will i lose? Also if you left the answer as 5/root 29 for 7ai will you lose any marks seeing as it was just a 2 mark question? Also for the 2nd part I got the right answer (apart from minus sign), but again didn't simplify my surd. do you reckon I'll have lost any marks?
7ai fine
7aii drop 1 mark -
Re: Mr M's OCR (not OCR MEI) Core 2 Answers May 2012Q2 prob drop 2 marks(Original post by saj1994)
HI Mr M,
On Q2ii) i got the wrong value for c instead of getting -4 i got -22, i did all the working out correct but i think its a calculation error, how many marks would i get for this?
On Q5aii) I put the sequence repeats itself every 2 terms, would i get a mark for this.
On Q7 I used the SOH CAH TOA rule and the pythagoras rule to get different answers would get any marks for this.
Q5 fine
Q7 no marks - it isn't a right angled triangle -
Re: Mr M's OCR (not OCR MEI) Core 2 Answers May 2012
Sorry for asking again, but it got buried earlier.
I didn't notice it asking for exact answers for question 7a so I worked them out to 3s.f.
Because I didn't realise that they had to be exact, my working was basically just using arctan etc.
I got all the right answers, but not exactly.
Is it worth any marks?
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Re: Mr M's OCR (not OCR MEI) Core 2 Answers May 2012about the same as usual in terms of difficulty and i don't guess boundaries(Original post by IShouldBeRevising_)
Mr M last question please, Do you think this papers was hard relative to the other c2 papers, also what raw mark do you think will be an A, Thanks -
Re: Mr M's OCR (not OCR MEI) Core 2 Answers May 2012Ok thanks(Original post by Mr M)
about the same as usual in terms of difficulty and i don't guess boundaries
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I used rules of logs to do it but obviously must have got something wrong somewhere because I ended up getting -1 with lots of decimal places, would using log rules to get that as my answer get me anything?(Original post by Mr M)
I don't know what you did so can't say but it doesn't look promising. -
Re: Mr M's OCR (not OCR MEI) Core 2 Answers May 2012That's exactly what I did! Even now I'm determined that the question asked that, I always double check my paper at the end... :/(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!
Mr M was it definitely (3+2x)^5 + (3-2x)^5? It wasn't the first one take away the next? -
Re: Mr M's OCR (not OCR MEI) Core 2 Answers May 2012Yes for segment(Original post by J DOT A)
Yeah MR M, I used the formula for segment...A=0.5r^2(theta-sintheta) with a value of 15/sqrt pi, would I get 2 method marks out of 3 for using the formula?
It's just that my r value was incorrect.
Also, You said I might loose 2 marks for getting incorrect r value..but wouldn't there be on for method?
Finally, for 7ii I got that answer but postive, I used a triangle and did the acute angle..how many marks would I drop?
Doesn't look like your method for r was right? If it was, 1 mark
Q7 drop 1 mark -
Re: Mr M's OCR (not OCR MEI) Core 2 Answers May 2012No I don't think you will get anything there, sorry!(Original post by TehCoolNerd)
Sorry for asking again, but it got buried earlier.
I didn't notice it asking for exact answers for question 7a so I worked them out to 3s.f.
Because I didn't realise that they had to be exact, my working was basically just using arctan etc.
I got all the right answers, but not exactly.
Is it worth any marks?
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Re: Mr M's OCR (not OCR MEI) Core 2 Answers May 2012i'm positive it is definitely +, i looked at it carefully... sorry(Original post by Nuttyclorox)
That's exactly what I did! Even now I'm determined that the question asked that, I always double check my paper at the end... :/
Mr M was it definitely (3+2x)^5 + (3-2x)^5? It wasn't the first one take away the next?
about both your misfortune and the terrible pun -
Re: Mr M's OCR (not OCR MEI) Core 2 Answers May 2012I don't think you will get anything, 1 mark at most by the sound of it(Original post by propertimbo)
I used rules of logs to do it but obviously must have got something wrong somewhere because I ended up getting -1 with lots of decimal places, would using log rules to get that as my answer get me anything? -
Re: Mr M's OCR (not OCR MEI) Core 2 Answers May 2012I'm not sure I can let you off for the pun. Hmm(Original post by kenann)
i'm positive it is definitely +, i looked at it carefully... sorry
about both your misfortune and the terrible pun -
Re: Mr M's OCR (not OCR MEI) Core 2 Answers May 2012
Mr M,
for 9bi) I incorrectly wrote 1 < y < 2 as i thought that r has to be between 0 and 1. Solving logs correctly? Would I obtain any marks whatsoever?
Also for 9bii) I put log to the base 2 of 64, instead of 8. Continuing with the correct method?
Would I obtain any marks for this also. Or does it stop once you go wrong. I always get confused about this?
And for the question 7, I'm also assuming that you would obtain no marks at all for using a decimal? -
Re: Mr M's OCR (not OCR MEI) Core 2 Answers May 2012
Mr M, for Question 7(a), for part (i) I just did Inverse Tan of 2/5 and then found the cosine of that, and put it down in decimal (correct but not the exact value). Did the same thing for part (ii) but found the obtuse angle of course. So both my answers were in decimal and not exact form. How many marks will I drop for that??? Thanks
Last edited by tahseen1995; 18-05-2012 at 14:06. -
Re: Mr M's OCR (not OCR MEI) Core 2 Answers May 20129bi) 1 mark(Original post by Kavzaz)
Mr M,
for 9bi) I incorrectly wrote 1 < y < 2 as i thought that r has to be between 0 and 1. Solving logs correctly? Would I obtain any marks whatsoever?
Also for 9bii) I put log to the base 2 of 64, instead of 8. Continuing with the correct method?
Would I obtain any marks for this also. Or does it stop once you go wrong. I always get confused about this?
And for the question 7, I'm also assuming that you would obtain no marks at all for using a decimal?
9bii Not sure what you have done really
7 no marks for using a decimal