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# OCR MEI Core 4 (C4 4754/01 and 4754/02) watch

1. (Original post by foolsihboy)
It was =/
LOLOLOL.

Honestly that must have been painful. Surely you only finished half an hour ago then?
2. (Original post by IchiCC)
Does anyone know how they do the UMS scale?

Because I think I did well in the actual paper, but messed up a bit in the comprehension.

Do they add the two raw marks together then convert to UMS, or do they work out a UMS for each paper separately, then add them together?
Combine then convert to UMS
Vector questions:

ii) to find the angle between the vertical and direction vector, I'm fairly sure you had to use a vertical direction such that (0,0,z) where z is any positive number as it was the line OZ. No matter what value for z you used, you'd notice that when finding costheta, the two values of z should cancel anyway.

iv) last part; you find the angle between normal direction to the plane and direction of AB. I then took this value away from 90degrees.

Again, not 100% on these, but I'm fairly certain they're right.
i did the same
apart from the last part i added 90degrees - again not sure!
4. It was really weird that ratio thing.

Knowing the values of C and A you then had to sub these into the x=2theta - sintheta

and then i did someting like OC-OA = AC

And using value for OA which was pi - 1 and then AC was pi + 1
and that was it
5. (Original post by -5-6-7-)
it cant be those values because it said OA and OB had a ratio of pi-1i+1
which is effectively 1:2
i got B is pi
and A is pi/2

however my working didnt really make sense, so ive no idea how i got that
i duno if its right but it makes sense?
I just did Length OA= pi-1
Length AB= 2pi-OA
=2pi-(pi-1)
=pi+1
6. (Original post by -5-6-7-)
it cant be those values because it said OA and OB had a ratio of pi-1i+1
which is effectively 1:2
i got B is pi
and A is pi/2

however my working didnt really make sense, so ive no idea how i got that
i duno if its right but it makes sense?
I got the same parameter values!
I think for A, I put y=0 and got θ = pi/2
and for B, went on the basis that the cos graph has a minimum when cosθ=-1 and which would make θ = pi. Dunno if that's right?
7. (Original post by morrison11)
I did 180-angle. Though I wasn't sure it was necessary, so I did it in kinda small writing.
I did that. No sure whether its right though.
8. (Original post by Miss_Chanel)
I got the same parameter values!
I think for A, I put y=0 and got θ = pi/2
and for B, went on the basis that the cos graph has a minimum when cosθ=-1 and which would make θ = pi. Dunno if that's right?
yep that was my method of working too! not sure how i get there i dont get parametric equations but the values fitted
9. (Original post by Miss_Chanel)
So do you remember what you got as the answer?
I think I used the same method and got roughly 72 degrees - anyone else?
Yeah I used (0,0,100) and got about 72 degrees. What did the people who used (0,0,1) get.

Other than Q3 I thought it was OK. Comprehension was good imo.

What did people get for that tan(theta+45) question. Q6 I think it was.
10. (Original post by The Stig's student cousin)
Yeah I used (0,0,100) and got about 72 degrees. What did the people who used (0,0,1) get.

Other than Q3 I thought it was OK. Comprehension was good imo.

What did people get for that tan(theta+45) question. Q6 I think it was.
I used (0, 0, 1) and got 72 degrees, same direction vector, but the calculations are slightly easier with (0, 0, 1).
11. Also what did people say for why Jenny was wrong? I said the trapezium rule gives an overestimate so using more strips would give a smaller value than the one in part (i) but I thought when a curve was increasing in gradient (as it was) the trapezium rule gave an underestimate.
12. (Original post by morrison11)
You've forgotten metres there..
i did all 3
13. (Original post by DeanT)
I used (0, 0, 1) and got 72 degrees, same direction vector, but the calculations are slightly easier with (0, 0, 1).
Cool, thanks.
14. (Original post by GenericStudent)
For the partial fractions question, did A=1 and B=-1? Because I swear I messed something up round there..
Thats what I got, and I think that's right
15. (Original post by Miss_Chanel)
So do you remember what you got as the answer?
I think I used the same method and got roughly 72 degrees - anyone else?
I got 72 as well, yes.

--

I took the angle away from 90 for the plane question, with a little diagram much like the one posted before.
16. (Original post by -5-6-7-)
it cant be those values because it said OA and OB had a ratio of pi-1i+1
which is effectively 1:2
i got B is pi
and A is pi/2

however my working didnt really make sense, so ive no idea how i got that
i duno if its right but it makes sense?
how i did somehow manage to make it fit that ratio, when i put the values into the x equation. took me forever though!
17. Yeah the partial fractions were A = 1, B = -1. I almost got caught out in the second part of that question, nearly forgot to multiply both sides by 3. If they didn't show the answer you needed I probably would have got that wrong
18. (Original post by The Stig's student cousin)
Yeah I used (0,0,100) and got about 72 degrees. What did the people who used (0,0,1) get.

Other than Q3 I thought it was OK. Comprehension was good imo.

What did people get for that tan(theta+45) question. Q6 I think it was.
erm, i got 0, and another answer, like 62 or something
19. (Original post by Scabo0o)
Thats what I got, and I think that's right
It had to be right, otherwise you couldnt do the second part, which incidentally I didn't see until I was half way through Q7, luckily I started Q6 on another page and had quite a bit of room under part (i) so glad I spotted it because it was an easy 5marks
20. (Original post by The Stig's student cousin)
Also what did people say for why Jenny was wrong? I said the trapezium rule gives an overestimate so using more strips would give a smaller value than the one in part (i) but I thought when a curve was increasing in gradient (as it was) the trapezium rule gave an underestimate.
http://www.mei.org.uk/files/papers/c407ja_1jd8q.pdf

take a look at question 2!

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