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# OCR Mei Numerical Methods, 16th May 2012

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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1. Re: (OCR) MEI NM - Wed 16 May 2012 AM
Oh yeah guys how did you guys talk about questions 5? The odd one about the spreadsheet.
2. Re: (OCR) MEI NM - Wed 16 May 2012 AM
(Original post by Reminisce)
Yes I did that, it just means that we had to round it when we found the midpoint but I did 6 dp so should been fine hopefully.
good good, what did you get your simpson rule ratio as?
3. Re: (OCR) MEI NM - Wed 16 May 2012 AM
(Original post by sreddy17)
good good, what did you get your simpson rule ratio as?
Mine was off probably because of rounding to midpoint - I got 0.07 something
4. Re: (OCR) MEI NM - Wed 16 May 2012 AM
ok cool, when it said to find the max and min value did you go back and find a max m4 and max t4 and min m4 and min t4 and then find max and min simpsons or what?
5. Re: (OCR) MEI NM - Wed 16 May 2012 AM
(Original post by sreddy17)
ok cool, when it said to find the max and min value did you go back and find a max m4 and max t4 and min m4 and min t4 and then find max and min simpsons or what?
Yeah I looked at the max possible error so its + or - 0.000 005 I used it in the T formulae and found that all of them give 0.000 01 as the mpe so (4T2n - Tn)/3 will still give an error of 0.000 01 so it my range was my value - 0.000 01 and my value + 0.00 01.
6. Re: (OCR) MEI NM - Wed 16 May 2012 AM
if you midpoint rule and trapezium rule to work out Simpson rule is right or wrong
7. Re: (OCR) MEI NM - Wed 16 May 2012 AM
and max/ min was for f(x) value not trapezium
8. Re: OCR Mei Numerical Methods, 16th May 2012
spreadsheet one was weird.. i swear it seemed to be changing the number of significant figures it was storing?
All of section A other than that was fine i thought, but section B, finding the max error of the simpsons rule if all the values of y were rounded to 5dp i just completely bull****ted, dont think i got it right at all, and ended up wasting loads of time on..
Also q7 i didnt finish, seemed odd they tested secant method and method of false position, seeing as they are pretty much the same formula, and both just take ages :L
9. Re: OCR Mei Numerical Methods, 16th May 2012
(Original post by sreddy17)
How did everyone find it? I thought it was ok except for the simpson from trap rule one and the spreadsheet one!
Don't the rules state NO DISCUSSION for 24 hours.
10. Re: OCR Mei Numerical Methods, 16th May 2012
(Original post by steve2005)
Don't the rules state NO DISCUSSION for 24 hours.
The rules are:

For Edexcel: morning exams may not be discussed until 12:00 midnight (UK time) and afternoon exams until 4:30 AM (UK time).
For STEP/CIE/IB: allow 24 hours to pass from the end of each exam before any discussion.
Oral exams: No discussion until the end of the exams season, from 28 June 2012.
Exams from the examination boards AQA, OCR, CCEA and WJEC (other than orals) are fine to talk about straight after the exams because these boards are UK based only.
Applied ICT exams: No discussion is permitted throughout the five day window for each exam.
Discussion of OCR exams is allowed straight after the exam.
11. Re: (OCR) MEI NM - Wed 16 May 2012 AM
(Original post by sreddy17)
ok cool, when it said to find the max and min value did you go back and find a max m4 and max t4 and min m4 and min t4 and then find max and min simpsons or what?
(Original post by Reminisce)
Yeah I looked at the max possible error so its + or - 0.000 005 I used it in the T formulae and found that all of them give 0.000 01 as the mpe so (4T2n - Tn)/3 will still give an error of 0.000 01 so it my range was my value - 0.000 01 and my value + 0.00 01.
I thought about it graphically. If the f(x) values are all 0.000005 higher (or lower) then the overall change in the area under the line would be 0.000005 multiplied by the difference between the limits (in this case 2).
12. Re: OCR Mei Numerical Methods, 16th May 2012
Though it was went ok, spreadsheet one took a bit of thinking and I had to blag my way through the part of the integration question where they asked if the f(x) values were rounded to 5dp, what did everyone else put for that? Ended up guessing at a relative error of 0.000005 for my answer, who knows what it was.

Effort when they asked to find simpsons rules from the trapezium rules too, having to find all the mid-point rules first, for just 6 marks!
13. Re: (OCR) MEI NM - Wed 16 May 2012 AM
(Original post by fluteflute)
I thought about it graphically. If the f(x) values are all 0.000005 higher (or lower) then the overall change in the area under the line would be 0.000005 multiplied by the difference between the limits (in this case 2).
what did you get for your range then?
14. Re: (OCR) MEI NM - Wed 16 May 2012 AM
Though it was went ok, spreadsheet one took a bit of thinking and I had to blag my way through the part of the integration question where they asked if the f(x) values were rounded to 5dp, what did everyone else put for that? Ended up guessing at a relative error of 0.000005 for my answer, had barely any time left as id left it and took a bit of a punt!

Reckon we'll still get full marks for calculating the midpoint rules first and using that relationship to find the simpsons rules, expecting us to know a relationship that isn't even in their textbook is outrageous!
15. Re: (OCR) MEI NM - Wed 16 May 2012 AM
(Original post by sreddy17)
what did you get for your range then?
I can't remember the values, but the basic idea was along the lines of:

1.74354365 < I < 1.74356365

Don't know if that's what they were looking for.
Last edited by fluteflute; 16-05-2012 at 18:05.
16. Re: OCR Mei Numerical Methods, 16th May 2012
(Original post by Orrin)
Though it was went ok, spreadsheet one took a bit of thinking and I had to blag my way through the part of the integration question where they asked if the f(x) values were rounded to 5dp, what did everyone else put for that? Ended up guessing at a relative error of 0.000005 for my answer, who knows what it was.

Effort when they asked to find simpsons rules from the trapezium rules too, having to find all the mid-point rules first, for just 6 marks!
I ended up blagging most of Section B. Section A was fine. The spreadsheet one i got (even though it was wordy). The integration one i guessed like Orrin above.

I disliked Section B Q7, it took a long time and due to the high amount of calculations needed felt i was sure to make a mistake somewhere along. At one part I wanted to just rip the paper up as I hate these sort of questions . (Fortunately I did not). I'll just have to wait and see for the results.

Good luck for everyone else by the way!
17. Re: (OCR) MEI NM - Wed 16 May 2012 AM
(Original post by fluteflute)
I can't remember the values, but the basic idea was along the lines of:

1.74354365 < I < 1.74356365

Don't know if that's what they were looking for.
YES if you confirm its plus or minus 0.000 01 then I'm soooooo relieved...
Last edited by Reminisce; 16-05-2012 at 18:18.
18. Re: OCR Mei Numerical Methods, 16th May 2012
(Original post by Orrin)
Though it was went ok, spreadsheet one took a bit of thinking and I had to blag my way through the part of the integration question where they asked if the f(x) values were rounded to 5dp, what did everyone else put for that? Ended up guessing at a relative error of 0.000005 for my answer, who knows what it was.

Effort when they asked to find simpsons rules from the trapezium rules too, having to find all the mid-point rules first, for just 6 marks!
Ahh i think they wanted you to use

so etc hence why they got you to work out T8, even though they only wanted 3 simpsons rule estimates
19. Re: OCR Mei Numerical Methods, 16th May 2012
(Original post by just george)
Ahh i think they wanted you to use

so etc hence why they got you to work out T8, even though they only wanted 3 simpsons rule estimates
That's what I did.
20. Re: OCR Mei Numerical Methods, 16th May 2012
Won't be happy if i've lost marks on that!

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