The Student Room Group

OCR MEI C4 Unofficial markscheme 2017

12/3/18 Update: I, as per forum rules, will not be distributing the papers I acquired after my exams. However, if people sat them for a mock or otherwise attained them, and would like some worked examples I'd be more than happy to help if you send me a PM, granted I can find the papers when i return home from Uni at the end of this term (27/3/18).

1) 2/(x+1) + 1/(x-2)
expansion was: 5/2-7/4x-17/8x^2

2) [-7,9,-2]
ii) 68.4

3) T4 less than T2 as trapezium rule overestimate so more strips gets closer to actual value
ii) 3.25 or something, h=0.5, work out x and y and use formula

4) theta = 18.43 or 161.56

5) a =1/5, b=-7/5

6)2rtP=kt+c so k=2B

7) 176/27 pi
ii) 3rt2/4

3/2(sinX) goes somewhere

8) rt5cos(X-1.107)
B=(1,1)
A = (0.6,0)
C = (-0.6,rt5)
angle B = 1.90 radians

Comprehension:
1) 0<x<1
ii) 1 or 0

2) 3/8
ii) b^2-4ac < 0 so no solutions

3) when k=2, pop tends to 0
when k=3 pop tends to 0.5
when k=4 pop oscillates between 0.5 and 0.75
when k=5 pop is unbounded

4) two next values:k= 3.5487 and 3.5696
ii) S = 1.273
iii) k>boundary for oscillations so "Chaos"

Comp was pretty hard, C4 was super standard :smile:

c3: https://www.thestudentroom.co.uk/showthread.php?t=4793944

My theoretical marks: C3; 87/90, C4; 82/90

my predicted boundaries:
100UMS - C3; 87 C4; 85
90UMS - C3; 81 C4; 79
80UMS - C3; 73 C4: 73
70UMS - C3; 67 C4; 68
60UMS - C3; 60 C4 62
(edited 6 years ago)

Scroll to see replies

Original post by Toffo132
Not sure if I've remembered all the questions or all of my answers but:

1) 2/(x+1) + 1/((x-2)
expansion was something like: 5(1-x+x^2)? maybe? can't remember

2) [-7,9,-2]
ii) 68.4

3) T4 less than T2 as trapezium rule overestimate so more strips gets closer to actual value
ii) 3.25 or something, h=0.5, work out x and y and use formula

4) theta = 18.43 or 161.56

5) a =1/5, b=-7/5

6)2rtP=kt+c so k=2B

7) 176/27 pi
ii) 3rt2/4

8) rt5cos(X-1.107)
B=(1,1)
A = (0.6,0)
C = (-0.6,rt5)
angle B = 1.40 radians

Comprehension:
1) 0.6
ii) 1 or 0

2) 3/8
ii) x=-1 or x=2 so does not satisfy 0<x<1

3) when k=2, pop tends to 0
when k=3 pop tends to 0.5
when k=4 pop oscillates between 0.5 and 0.75
when k=5 pop is unbounded

4) two next values:k= 3.5487 and 3.5696
ii) S = 1.273
iii) k>boundary for oscillations so "Chaos"

Comp was pretty hard, C4 was super standard :smile:


I think I'd agree with most of this. Can't quite remember everything.

I don't think I got that as the expansion (first question) - Pretty sure I had fractions as coefficients of x and x^2
(edited 6 years ago)
Reply 2
Original post by harryleavey
I think I'd agree with most of this. Can't quite remember everything.

I don't think I got that as the expansion - Pretty sure I had fractions as coefficients of x and x^2


yeah can't remember the question, do you?
Reply 3
Pretty sure the expansion you had to do was 1/(2-x) + 2/(1+x)
Yeah I agree with everything apart from the expansion, I got 4-x+5/2 x^2
(edited 6 years ago)
Reply 4
Original post by Toffo132
Not sure if I've remembered all the questions or all of my answers but:

1) 2/(x+1) + 1/((x-2)
expansion was something like: 5(1-x+x^2)? maybe? can't remember

2) [-7,9,-2]
ii) 68.4

3) T4 less than T2 as trapezium rule overestimate so more strips gets closer to actual value
ii) 3.25 or something, h=0.5, work out x and y and use formula

4) theta = 18.43 or 161.56

5) a =1/5, b=-7/5

6)2rtP=kt+c so k=2B

7) 176/27 pi
ii) 3rt2/4

8) rt5cos(X-1.107)
B=(1,1)
A = (0.6,0)
C = (-0.6,rt5)
angle B = 1.40 radians

Comprehension:
1) 0.6
ii) 1 or 0

2) 3/8
ii) x=-1 or x=2 so does not satisfy 0<x<1

3) when k=2, pop tends to 0
when k=3 pop tends to 0.5
when k=4 pop oscillates between 0.5 and 0.75
when k=5 pop is unbounded

4) two next values:k= 3.5487 and 3.5696
ii) S = 1.273
iii) k>boundary for oscillations so "Chaos"

Comp was pretty hard, C4 was super standard :smile:



just realised i used h=2 instead of h=1/2 in the trapezium rule question. any idea how many marks i would lose? everything else was correct im hoping for follow through marks :frown:
(edited 6 years ago)
Reply 5
Original post by Toffo132
Not sure if I've remembered all the questions or all of my answers but:

1) 2/(x+1) + 1/((x-2)
expansion was something like: 5(1-x+x^2)? maybe? can't remember

2) [-7,9,-2]
ii) 68.4

3) T4 less than T2 as trapezium rule overestimate so more strips gets closer to actual value
ii) 3.25 or something, h=0.5, work out x and y and use formula

4) theta = 18.43 or 161.56

5) a =1/5, b=-7/5

6)2rtP=kt+c so k=2B

7) 176/27 pi
ii) 3rt2/4

3/2(sinX) goes somewhere

8) rt5cos(X-1.107)
B=(1,1)
A = (0.6,0)
C = (-0.6,rt5)
angle B = 1.40 radians

Comprehension:
1) 0.6
ii) 1 or 0

2) 3/8
ii) x=-1 or x=2 so does not satisfy 0<x<1

3) when k=2, pop tends to 0
when k=3 pop tends to 0.5
when k=4 pop oscillates between 0.5 and 0.75
when k=5 pop is unbounded

4) two next values:k= 3.5487 and 3.5696
ii) S = 1.273
iii) k>boundary for oscillations so "Chaos"

Comp was pretty hard, C4 was super standard :smile:


also for the expansion would you lose marks for not saying when the expansion was valid? forgot that aswell :angry::angry:
(edited 6 years ago)
Reply 6
Original post by jcm420
also for the expansion would you lose marks for not saying when the expansion was valid? forgot that aswell :angry::angry:


nah, didn't ask for it in this case. Likely cos there were multiple terms of "x"
Reply 7
Original post by Milnos106
Pretty sure the expansion you had to do was 1/(2-x) + 2/(1+x)
Yeah I agree with everything apart from the expansion, I got 4-x+5/2 x^2


are you sure it was 2/(1+x)? i seem to remember them both being 1/ but maybe im wrong
The last angle i think was 1.90 rads
Original post by jcm420
also for the expansion would you lose marks for not saying when the expansion was valid? forgot that aswell :angry::angry:


It didn't ask. So don't worry about that.

I wrote it anyway, as I'm so used to writing it for expansions - I didn't see what I had to lose.
Reply 10
redid the expansion, correct answer is above.
Reply 11
Original post by harryleavey
It didn't ask. So don't worry about that.

I wrote it anyway, as I'm so used to writing it for expansions - I didn't see what I had to lose.


ok thanks! :biggrin:
Original post by Toffo132
Not sure if I've remembered all the questions or all of my answers but:

1) 2/(x+1) + 1/((x-2)
expansion was something like: 5(1-x+x^2)? maybe? can't remember

2) [-7,9,-2]
ii) 68.4

3) T4 less than T2 as trapezium rule overestimate so more strips gets closer to actual value
ii) 3.25 or something, h=0.5, work out x and y and use formula

4) theta = 18.43 or 161.56

5) a =1/5, b=-7/5

6)2rtP=kt+c so k=2B

7) 176/27 pi
ii) 3rt2/4

3/2(sinX) goes somewhere

8) rt5cos(X-1.107)
B=(1,1)
A = (0.6,0)
C = (-0.6,rt5)
angle B = 1.40 radians

Comprehension:
1) 0.6
ii) 1 or 0

2) 3/8
ii) x=-1 or x=2 so does not satisfy 0<x<1

3) when k=2, pop tends to 0
when k=3 pop tends to 0.5
when k=4 pop oscillates between 0.5 and 0.75
when k=5 pop is unbounded

4) two next values:k= 3.5487 and 3.5696
ii) S = 1.273
iii) k>boundary for oscillations so "Chaos"

Comp was pretty hard, C4 was super standard :smile:



Wow I don't think I got more than like 2 marks on the comprehension lol

Actual paper went well for me though, reckon I've done enough to get the overall B that I need for uni
Reply 13
Original post by Toffo132
redid the expansion, correct answer is above.


do you remember the marks per question? since you made the markscheme and that. would help loads
Also the second part of the first question in the comprehension didn't include x0 = 0 as it said from x1 onwards, xn = 0. If x0 was 0 then xn would be 0 from before x1, hard to explain but hope you understand
Reply 15
Original post by JamieHarris1998
Wow I don't think I got more than like 2 marks on the comprehension lol

Actual paper went well for me though, reckon I've done enough to get the overall B that I need for uni


we're in the same boat lad hahaha except i need an A :s-smilie::frown:
Original post by jcm420
are you sure it was 2/(1+x)? i seem to remember them both being 1/ but maybe im wrong


If you re-expand 2/(1+x) + 1/(2-x) you get 5-x which was what the question originally had
(edited 6 years ago)
Reply 17
Original post by OscarFrith1
Also the second part of the first question in the comprehension didn't include x0 = 0 as it said from x1 onwards, xn = 0. If x0 was 0 then xn would be 0 from before x1, hard to explain but hope you understand


Still 0 from x1 onwards, just also 0 at x0
Original post by jcm420
we're in the same boat lad hahaha except i need an A :s-smilie::frown:


Yeah,I needed an A for my firm offer but a B for my 2nd choice. Was on track for an A with the first year stuff and S2 but C3 and C4 have killed it for me
Reply 19
Original post by jcm420
do you remember the marks per question? since you made the markscheme and that. would help loads


[5]
[2] [4]
[2] [4]
[6]
[6]
[3] [4]

[4] [5] [9]
[5][5][3][5]

[1][1]
[2][2]
[6]
[3][2][1]

I think! if anyone can get ahold of the paper i can give more accurate answers!

Quick Reply

Latest