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

Mr M I Had the right answers for number 7 but i put them into decimals not as you stated would i still get the marks?

Wow that's lucky. I completely forgot the equation to work this out so I just guessed 10. Then I decided 10 was too low and put 20.

I went back later in the paper and decided that 20 was too high, and settled with 15!

Will I still get 2 marks since I got the right answer? Even though there is no working out?

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

for questio 7 if you got the right answer but didnt use the method which will probably be on the markscheme ( the traingle one) would you still get the marks? i ended up using sin^2 +cos ^2 =1 and then devided by cos^2 and did a whole bunch of other stuff :/

Mr M, on question 7ai) I left it as 5/root29. Would I loose a mark for not writing it in standard form?

For question 7 I put the answer in decimal form, correct to three significant figures. Would that mean that I get no marks?

What about reoccuring sequence of o.5 and 4, thats what I put would I get "reoccuring"


also for 0.5<x<2 would I have got any marks for x>2 because i calculated that it needed 2 correctly but did put it the right way around

http://www.thestudentroom.co.uk/attachment.php?attachmentid=149020&d=1337341593
http://www.thestudentroom.co.uk/attachment.php?attachmentid=149019&d=1337341560
this was posted by someone else btw

What was the technique for doing question 7 part A?

Hi Mr M,

For the question that asked us to find the values of y for which the GP was valid, I put the modulus of y is less than something...I can't remember exactly what the number was but is there a correct version of the answer involving a modulus sign?

Thanks!

Mr M did qu 6iii) have to be an exact value? I wrote 208/3 BUT then wrote the decimal version next to it and underlined it do you think I'd get the mark??

Mr M's OCR (not OCR MEI) Core 2 Answers May 2012

7. (a) (i) $\frac{5 \sqrt{29}}{29}$ (2 marks)

(ii) $\frac{-2\sqrt{10}}{7}$ (3 marks)



Hi Mr M

Thank again for the mark scheme!
I got
7ai) 5 divided by root 29
ii) 2 root 10 divided by 7 (no minus)

So so you know if these will be marked correct?

Thanks again

For the ratio one, will 0<y<2 get 1 mark?

also what do you think the marks for 100ums would be?

MR M PLEASE HELP. for question three i STUPIDLY did not read the pie after 45, but all the rest of my working was correct. So how many marks will i lose for question three? Also for question 7 I left my answers unsimplified but they were correct, so do i loose marks? THANKS

damn i did the exact same.
For q3 i didn't read the pi part which means i got 3ii wrong too.
q7 also, I did all of my answers in decimal form instead of surd form.
I think mr m has stopped responding, so i guess we'll all have to wait till august

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

for question 4, i got to; -4sin²(x) + 7sin(x) - 3 =0, but I stupidly missed out a negative sign using the quadratic formula, so i got sin(x) = -1,-3/4 , not 1 and 3/4. Obviously I got the wrong answers, but how many marks would i have lost as i had the correct method?

Other than that it was quite a good paper. the only thing that caught me out was Q7.

For all of question 7a), if you do inverse trig functions then cos x to get a decimal and for 7b) if you do sin60/8 x 6 to get a decimal, where in all of these circumstances the decimal is equal to your answers, will you still get the marks?