You are Here: Home >< Maths

# OCR MEI C3 Mathematics June 2016 - Official Thread watch

1. How many marks was 8ii and iii and does anyone have a pic of the paper? Or can post an unofficial mark scheme with the mark breakdown in each question
2. (Original post by fazee)
UNOFFICIAL MARK SCHEME:

1. Integrate 1 + cos(0.5x) between limits of 0 and pi/2. Answer is pi/2 + root2

2. Solve for x. Answer is x = ln2

3. Can't remember the context. Answer is 4ln4 - 4 - alternatively may be written as 4(ln4 -1) or ln256 - 4 or any equivalent form.

4. |2x+1| = -x. First case, 2x+1 = -x, gives 3x+1 = 0, 3x = -1, x = -1/3
Second case, -(2x+1) = -x, negate both sides to give 2x+1 = x, x+1 = 0, x = -1
Alternative approach, square both sides, 4x2 + 4x + 1 = x2, 3x2 + 4x + 1 = 0, (x+1)(3x+1) = 0, x= -1, x = -1/3 as before

5i. V = 4root(h3+1) - 4. dV/dh using chain rule gives 4*1/2(h3+1)-1/2 * 3h2 = 6h2 * (h3+1)-1/2. Substituting h=2 gives dV/dh = 8 (feel free to check this for yourself).
5ii. dh/dt = dh/dV * dV/dt = 1/8 * 0.4 = 0.4/8 = 0.05

6i. Can't remember the context. Answer is root3 /3
6ii.Transformation is first translate 1 unit to the right, THEN stretch parallel to y-axis, scale factor 1/2

7. x2n-1 = (xn+1)(xn-1). Substituting for x=2, 2n has to be even, so it's a product of two consecutive odd numbers, so one of those must be divisible by 3, so their product is divisible by 3. That's why I put anyway, I've seen someone say it's not right, so not completely sure about this one.

8i. Differentiate using quotient rule, then multiply your result by 2root(x+4), to obtain dy/dx in the form given.
8ii. Using equation for y, asymptote is x= -4, so x coordinate of P is -4. Use dy/dx for x=0, to show that tangent is y = 0.5x (y-intercept c is 0). Then y = 0.5 * -4 = -2, so P is (-4,-2)
8iii.Area under the curve is found by integration to be 14/3. Area of triangle with vertices O,Q and (5,0) is 1/2 * 5 * 5/2 = 25/4
So area of required region is 25/4 - 14/3 = 19/12

9i. y = e2x + ke-2x. When x=0, y = 1 + k*1 = 1+k
9iii. Answer simplifies to (0.5k - 1/2) - (1/2 - 0.5k) = 0.5k - 1/2 - 1/2 + 0.5k = k - 1
9ivA. Replace x with (x+ 0.25lnk), to give g(x) = rootk(e2x + e-2x).
9ivB. g(-x) = g(x), so g(x) is an even function.
9ivC. f(x) is symmetrical about the line x = 0.25lnk. This can be deduced because g(x) is f(x) translated 0.25lnk units to the left. g(x) is even, so is symmetrical about the y-axis i.e. symmetrical about line x=0. f(x) is g(x) translated 0.25lnk units to the right, therefore its line of symmetry is x = 0.25lnk. Full reasoning will probably be required for all 3 of these marks.

These are the answers of my friend, who does Additional Further Maths, so I think they should all be right, or most of them anyway. Of course, feedback is more than welcome, if I've made a mistake please point it out.

I think boundaries will be 88 or 89 for 100 UMS (out of 90, for exam and coursework). 90% should be 80 or 81, and A should be 72 or 73. Difference between each grade will be about 7 or 8 marks.

I had the exact same for every single answer. General consensus seems that these are the correct answers too.
I got 15/18 for coursework + hopefully 65-72 out of 72 for the paper (assuming I made some errors) so hopefully that will put me close to 100ish ums (fingers crossed)
overall I found it quite an easy paper - hope every else did well. no point stressing now as there is nothing that can be done
3. Also as response to some of the people debating the proof, this is what I put:

(2^n -1)(2^n + 1)
Since 2^n = 2,4,8,16,32,64.... so on
therefore 2^n - 1= 1,3,(7),15,(31),63... every other number is divisible by three
also 2^n + 1 = 3,(5),9,(17),33,(65)... every other number is divisible by three
therefore the product of (2^n -1)(2^n +1) must be divisible by three as one of the factors is divisible by three
the divisible factor alternates between every value of n

that is what I put I'm not sure if that is exactly how you 'prove' the conjecture but makes sense to me
4. (Original post by Leechayy)
That's the translated one isn't it?p

Posted from TSR Mobile
:P well the un-translated one certainly isn't 2cosh2x
5. Out of interest what did people get for the coursework component seeing as that can cripple your grade.
6. thanks !
(Original post by ComputerMaths97)
Add the score from your coursework to your raw mark from the exam, giving a score out of 90, then you get corresponding ums out of 100.
7. (Original post by Aph)
Out of interest what did people get for the coursework component seeing as that can cripple your grade.
17/18
8. for question 9.ii i showed that the minimum point has x co ordinate of 1/4ln4 and then i subbed that back into f(x) to find out the y co ordinate but i got an incorrect y co ordinate. how many marks in the question will i lose because of this
9. (Original post by Aph)
Out of interest what did people get for the coursework component seeing as that can cripple your grade.
16/18
10. (Original post by Aph)
Out of interest what did people get for the coursework component seeing as that can cripple your grade.
18/18
11. For question 3 I didn't sketch the graph, how many marks is that out of 4?
And 8iii how many marks is integration of just the curb work out of 9?
12. I think I got 46/72 in this and I got 15/18 in my coursework, what would I average out with?
What does everyone think the grade boundaries for B will be?
13. Can anyone tell me that if i got 69/72 for c3 paper and 13/18 for c3 coursework, what is the UMS out of 100 for c3 please?
14. (Original post by fkjames)
Can anyone tell me that if i got 69/72 for c3 paper and 13/18 for c3 coursework, what is the UMS out of 100 for c3 please?
Since a lot of people are asking this: here's MEI's UMS conversion site. You can estimate based on previous years, but remember that it changes slightly based on the difficulty of the exam. http://www.ocr.org.uk/i-want-to/conv...-marks-to-ums/
15. (Original post by y0uSmartass)
I think I got 46/72 in this and I got 15/18 in my coursework, what would I average out with?
What does everyone think the grade boundaries for B will be?
Based on previous years that would be a mid-C
16. (Original post by mrbazz12)
Okay paper apart from 2 things:

1. For the proof question, I wrote down the difference of two squares i.e. (X^n + 1)(X^n - 1) and then had a mind blank, so will I get 1 mark for that? (out of the 4)

2. The modulus question I used the 'square both sides' method only to forget to square one of the sides (the X on the other side to the | 2x - 1 |) so got an answer of X = -1 and X = 1/4. How many marks will I lose for this?

Apart from those lost marks^ I thought paper was alright.
17. Can anyone remember question 3? What was the graph you had to draw?
18. (Original post by mrbazz12)
You would definitely get the first mark as it asked for that in the question.

You would probably lose 2 marks on the second one, the final A1 for the wrong answer, and probably a M1 mark
19. can somebody please say the marks given to each question please haha
20. (Original post by mrbazz12)
Can anyone remember question 3? What was the graph you had to draw?
the graph was the modulus function and y=-x. You had to show the intersects.

### Related university courses

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:
Updated: May 9, 2017
The home of Results and Clearing

### 2,965

people online now

### 1,567,000

students helped last year
Today on TSR

### University open days

1. London Metropolitan University
Sat, 18 Aug '18
2. Edge Hill University
Sat, 18 Aug '18
3. Bournemouth University
Sat, 18 Aug '18
Poll
Useful resources

Can you help? Study help unanswered threadsStudy Help rules and posting guidelinesLaTex guide for writing equations on TSR

## Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE