The Student Room Group
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>

OCR C2 exam Wed 25th May

Scroll to see replies

Is anyone going to make an unofficial mark scheme?
Reply 81
Avatar for h3rmit
h3rmit
15
Original post by student199919
depending on what it's out of, maybe like 1/2 marks? what was the actual answer for the stretch one of 3^x-2?


I put stretch parallel to y axis by factor 1/9 , since multiplying by 1/3^2 gives 3^(x-2)
Reply 82
Avatar for AlfieH
AlfieH
2
I am gonna start an unofficial mark scheme - I think this is about correct! :smile:

1i) 10cm (2m)

1ii) 5.04cm (2m)

2i) 3/10π (2m)

2ii) 20.4cm (3m)

3i) 27+27kx+9k^2x^2+k^3x^3 (4m)

3ii) +/-√3 (2m)

4i) log base 3 x^2/x+4 (2m)

4ii) x=12 (4m)

5a) x^4/2-x^3+2x^2-6x (3m)

5bi) -6/a+2/a^2+4 (4m)

5bii) 4 (1m)

6i) k=91 (3m)

6ii) Sum of terms = 978 (2m)

6iii) N=38 (6m)

7i) R=0, quotient = x^2-4x+3 (3m)

7ii) (x+1), (x-1), (x-3) (3m)

7iii) Prove (2m)

7iv) 512/15 (4m)

8i) Translation 2 units in positive x direction (2m)

8ii) Stretch scale factor 1/9 in y direction (2m)

8iii) Sketch, crosses y at (0,1/9) (2m)

8iv) x=6.73 (3m)

8v) Area =9.60 (3m)

9i) 2π/a (1m)

9ii) a=5/3 and k=√3/2 (3m)

9iii) π/3a and ? (4m)
(edited 7 years ago)
Reply 83
Avatar for amc1234
amc1234
Original post by _Orion_
What did people get for N with the arithmetic and geometric series?

Posted from TSR Mobile


Honestly did that so many times and persistently got that N > 0
Reply 84
Avatar for flirps
flirps
1
Original post by student199919
i think i got something like 38, i'm probably wrong


I got 38 as well, i spoke to a few people and they got the same
Original post by AlfieH
I am gonna start an unofficial mark scheme - I think this is about correct! :smile:

1i) 10cm

1ii) 5.04cm

2i) 3/10π

2ii) 20.4cm

3i) 27+27kx+9k^2x^2+k^3x^3

3ii) +/-√3

4i) log base 3 x^2/x+4

4ii) x=12

5a) x^4/2-x^3+2x^2-6x

5bi) -6/a+2/a^2+4

5bii) 4

6i) k=91

6ii) Sum of terms = 978

6iii) N=38

7i) R=0, quotient = x^2-4x+3

7ii) (x+1), (x-1), (x-3)

7iii) Prove

7iv) 512/15

8i) Translation 2 units in positive x direction

8ii) Stretch scale factor 1/9 in y direction

8iii) Sketch, crosses y at (0,1/9)

8iv) x=6.73

8v) Area =9.60

9i) Not sure - please add

9ii) a=5/3 and k=√3/2

9iii) Not sure - please add


q9i 2pi/a
9iii i think is pi/3a and 4pi/3a
(edited 7 years ago)
3ii is wrong shouldn't it be k=0 and k=1/9
Reply 87
Avatar for czj1997
czj1997
8
for 5bi) -6/a+2/a^2+4
if i left it as -6a^-1 + 2a^-2 + 4 will any marks be deducted?

and if i forgot to square and cube k in q3, do i lose a few marks or all?
Reply 88
Avatar for AlfieH
AlfieH
2
Original post by goharis123
3ii is wrong shouldn't it be k=0 and k=1/9


They wanted coefficient of x^2 to equal the constant. The constant was 27 in this case so 9k^2=27 therefore k= +/- root 3.

I think? Many others seemed to get this and it was only 2 marks. I may be wrong.
Reply 89
Avatar for AlfieH
AlfieH
2
Original post by czj1997
for 5bi) -6/a+2/a^2+4
if i left it as -6a^-1 + 2a^-2 + 4 will any marks be deducted?

and if i forgot to square and cube k in q3, do i lose a few marks or all?


Nothing lost on 5bi.

It was only 2 marks so probably dropped 2.
Reply 90
Avatar for AlfieH
AlfieH
2
Original post by sandpitturtle
q9i 2pi
9iii i think is pi/3a and 4pi/3a


What about the stretch in a? I think maybe it is 2pi/a?

I got pi/3a as one solution but for some reason 2pi/3a for the other haha.
Reply 91
Avatar for flirps
flirps
1
I got that k was + or - 1/3
Original post by AlfieH
What about the stretch in a? I think maybe it is 2pi/a?

I got pi/3a as one solution but for some reason 2pi/3a for the other haha.


yeah thats right! sorry must've missed typing that but luckily i remember writing it for the exam:smile:
and not sure about the last one really everyone got different things haha
Original post by AlfieH
They wanted coefficient of x^2 to equal the constant. The constant was 27 in this case so 9k^2=27 therefore k= +/- root 3.

I think? Many others seemed to get this and it was only 2 marks. I may be wrong.


I think K was the constant and so 9k^2=k so
9k^2-k =0 so k(9k-1)
And so k=0 and k=1/9 I may be wrong I dont know
9ii) is 7π/a
See working out in the attached photo

Posted from TSR Mobile
(edited 7 years ago)
Original post by AlfieH
What about the stretch in a? I think maybe it is 2pi/a?

I got pi/3a as one solution but for some reason 2pi/3a for the other haha.


yeah 2pi/3a should be right, its amazing how quickly answers are forgotten after exams i have no idea if i put 2 or 4 on the top now
Reply 96
Avatar for AlfieH
AlfieH
2
Original post by sandpitturtle
yeah thats right! sorry must've missed typing that but luckily i remember writing it for the exam:smile:
and not sure about the last one really everyone got different things haha


My logic was first solution is π/3a therefor π-π/3a = 2π/3a...

Probably wrong - only a mark at least.
Shall we put the mark scheme in Google Docs?

https://docs.google.com/document/d/1lg3D_EJguObEJTdby539CpO8zl0BwDfXOkdEsoArVk0/edit?usp=sharing
Overall, i think the paper was fine, maybe apart from 9ii, which I did not manage to solve, but lost some stupid marks here and there. Think the grade boundaries will be around the same as usual, e.g. 58-59 for A
Does anyone know how many marks each question was to add to mark scheme?

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you