OCR (not OCR MEI) Core 3 answers Jan 2011

You can change it by cliking edit on the opening post and changing it in the title box there

I left it as $\mathrm{cosec}\ \alpha + \mathrm{cosec}\ \beta = 3\pi$ - will I drop one mark or all two?

Ahh okay thanks! stupid stupid mistake.
Okay, now for the killer question.... I used tan2(theta)=2tanA/1-Tan^2A
Therefore, I did Tan4a=2tan2A/1-tan^2A.
I got the correct tanx and cotx values, however I accidently subbed in tanx=1/4 in my tan4a equation, getting so I ended up with 2*2*1/4 divided by 1-2*1/4^2
and got something like 5/something
How many marks would I have lost for that question?

Wow overall this went better than expected. I think i got it all right apart from not putting the y co-ord for 6ii (how many marks will I lose for this) and I think i may have messed up the simpson's rule although im unsure . Anyway thanks Mr.M as always and i'm glad you said C3 was the hardest so far this session. Good luck everyone and by the way, what's the date in march for the results.

Thanks for your reply, i think i know what i have done i only wrote the x coordinate for P. How many mark do you think i will drop? it was out of 5?
Thanks.

What do you think the UMS will be for 71/72. Any chance of it being 100?

8.

ii) $\beta = 3\pi - \alpha$ (2 marks)

b)

ii) $\frac{225}{322}$ (6 marks)


9.

b) Show and (5 marks)

That isn't correct but you might get 1 mark for mentioning 3pi.

high chance

Hi Mr M,can you show a step by step working of 9ii
cus I left it as f(x) > e^(ln k/2)+ke^(-ln k/2)
???

10th march

Mr M, I already thanked you, but since posting this (about 15 mins ago) you've responded to mine and numerous others' questions. Honestly, I think i speak for everyone when saying, thank you very much.

Thanks for the solution!!
Any idea if how many marks I may lose for just stopping there?
And would I lose any marks for writing f(x)?