You are Here: Home

# OCR MEI FP1 May 18th 2012 PRE/POST DISCUSSION!

Announcements Posted on
Take our survey to be in with the chance of winning a £50 Amazon voucher or one of 5 x £10 Amazon vouchers 28-05-2016
1. (Original post by johnstong)
Does anyone know where the marks would come from for the inverse of the 3x3 matrix A? I'm a bit worried as it was 5 marks
This is just a guess going from previous past papers / judgement, but:

M1 mark for use of B
M2 mark for 79 or 1/79 seen
M3 mark for substituting in k=-3 (maybe, I can't remember 3 days later whether this was it / necessary for this part of the question)
A2 for for correct inverse (minus one for each error?)
2. ahh nice one thanks. I just stated AB at the top (with the k substituted in) then put 1/79 B do you think that would get me full marks then?
3. (Original post by johnstong)
ahh nice one thanks. I just stated AB at the top (with the k substituted in) then put 1/79 B do you think that would get me full marks then?
If you got the right answer, then yes. It wasn't really a question where you had to show vast quantities of working.
4. negged for doing well in an exam tut tut
5. Does anyone have the unofficial mark scheme
6. (Original post by doreyFP)
Does anyone have the unofficial mark scheme
na but quote me on any questions and I will tell you the answers...
7. (Original post by bossman42)
Yeah I got something like that too.

But how did you find the det of a 3x3 matrix :|
You didn't have to, you could work out the inverse another way, the det wasn't involved (it's on the FP2 spec).

What you had to do is re-arrange them like this (I can't remember the question exactly so excuse me if 49 isn't the right multiplier, I might have it mixed up with a practise exam I did XD)

AB = 49I
A-1AB = A-149I
B = 49A-1
A-1 = B/49
8. does anyone have the past paper? or a mark scheme to help me out

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: December 10, 2012
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

### Don't be a half-term hermit

How to revise this week and still have a life