You are Here: Home >< Maths

# OCR (not MEI) C1 13/05/13 Watch

1. (Original post by eggfriedrice)
I agree. The paper wasn't particularly hard. );
2. (Original post by Dugald)
Dy/dx=-3x^2+6x+4-k
k=-5 so dy/dx=3x^2+6x+9

3x^2+6x+9=9
3x^2+6x=0
3x(x+2)=0
x=0 or x=-2

I did this wrong because instead of doing 4-(-5) while differentiating I did 4-5 so go -1 on the end instead of 9 which gave me a quadratic with no real routes. So I couldn't attempt to find x or y.

How many marks will I lose?

How
First you say the dy/dx = -3x^2 ect.
Then you say dy/dx = 3x^2 ect.

I dont understand where the Negative has come from. Was the original equation; (x-1)(x^2+4x+k)?
3. (Original post by Rrobba)
I put the values of x and y into the original equation to see if they satisfied it. Putting x = -2 into the equation gave y = -27. The other value for x did not satisfy the equation and gave a different value for y.
How did you know it didn't satisfy the equation?

(Original post by BankOfPigs)
Not x-1.

you divide by 1-x

I think you get something like:

y = 9x -9 = -9(1-x)
y = (1-x)(x^2+4x+k)

So -9 = x^2+4x+k
Since k = -5

0 = x^2+4x+4 or (x+2)^2, which shows the repeated root.

At least thats how i did it.
Aha ok, I did a different method xD
4. (Original post by eggfriedrice)
Yup, I got 9/2 too.
****, left it as root 81/4. Will i lose the answer mark?

Posted from TSR Mobile
5. (Original post by Cowcat)
Do you even get 'error carried forward' marks in A level?
Yeah you do for some questions, I've seen it in the past paper mark schemes a few times.
6. (Original post by flyhigh99)
off the top of my head 61
7. (Original post by eggfriedrice)
Ah I did not think of that. you're probably right.
I did the same, and put down both we will lose 1-2 marks maximum. Surely wait for mr m for a mark scheme?

Posted from TSR Mobile
8. (Original post by hannah1258)
i did something very similar. Instead of making it equal to -3 i did dy/dx and then put in -3 for x and got some wierd answer which then made the part 3 completly wrong
will there be method marks for this?
Someone please put my mind at ease out of 12 (have a guess) how many method marks would I get???
9. (Original post by gibjb)
for the last part i know you had to equate the dy/dx of the curve to 9 and solve to get x. i did this but got 2 x coordinates so i didnt know which one to choose and stopped there. how many marks out of the 5 do you think i would have gotten?? and could anyone explain what you had to do after that step?
You had to say x could not equal zero because the gradient of 9x-9 is positive and at x the gradient was negative. I got (-2,-27) or something similar...
10. (Original post by flyhigh99)
No :s last year was 61 for an A I think.

(Original post by cheetahs56)
****, left it as root 81/4. Will i lose the answer mark?

Posted from TSR Mobile
Aha, I did that and realised root a square would just cancel out. Hmm I'm not sure, at most you'll lose one mark.
11. (Original post by princess_parisa_22)
can we compile a question paper together on here if we're allowed? these answers will be pretty useless unless everyone remembers what they wrote, and i'm sure not everyone will =/ i have a bad memory
If you wait until about 6:30-7 Mr.M will be posting up the answers
However, if anyone has the paper could they scan it and post it?
12. (Original post by Ellie_Rosa)
Which minimum point?
the one where you had to complete the square and give the coordinates of the minimum point/vertex
13. (Original post by gibjb)
for the last part i know you had to equate the dy/dx of the curve to 9 and solve to get x. i did this but got 2 x coordinates so i didnt know which one to choose and stopped there. how many marks out of the 5 do you think i would have gotten?? and could anyone explain what you had to do after that step?

I got the x co-ordinates, then used them to find out the y co-ordinates. Then to find out with co-ordinates are the correct ones I put them back into the original curve equation, and the ones that equalled 0 showed it was a tangent at that point, I think that is right? So I would guess you would only drop 1 mark, 2 tops.
14. (Original post by Goods)
I did the same, and put down both we will lose 1-2 marks maximum. Surely wait for mr m for a mark scheme?

Posted from TSR Mobile
Hopefully it's just one mark, I was hoping for 100% >.> darn.
15. (Original post by Pataiiii)
For the circles question, was the centre - (0,-4) or (-4,0)???
(0,-4)
16. (Original post by Pataiiii)
For the circles question, was the centre - (0,-4) or (-4,0)???
i got (0,-4)
17. (Original post by Whyllee)
Someone please put my mind at ease out of 12 (have a guess) how many method marks would I get???
I would guess 6-7 provided your method was correct bar the arithmetical error

Posted from TSR Mobile
18. (Original post by gibjb)
for the last part i know you had to equate the dy/dx of the curve to 9 and solve to get x. i did this but got 2 x coordinates so i didnt know which one to choose and stopped there. how many marks out of the 5 do you think i would have gotten?? and could anyone explain what you had to do after that step?
I got 2 x values and then substituted them into the equation of the curve to get two corresponding y values. Then I subbed these values into y=9x - 9 and only x=-2 and y=-27 worked. My other values were x=0 and y=-5 which don't work in y=9x-9
19. Guys, for the inequalities question
3-8x>4
Did you get x<-1/8 or x>-1/8
20. (Original post by Goods)
I would guess 6-7 provided your method was correct bar the arithmetical error

Posted from TSR Mobile
Thank you I know it's just a guess but thanks *sigh of relief*

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 15, 2013
Today on TSR

### Anxious about my Oxford offer

What should I do?

### 3 unconditional offers - can't decide!

Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• 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
Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• 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