(Original post by stefany-a)
did anyone use vector technique to find the ratio for section B ?
and for the shaded area question I found the area between 9 and 0, then found the area between 9 and 4.5 and toke it away from the area between 9 and 0 - do you guys think I got 0 marks for that question ?
I think that's a perfectly valid method. It's what I did anyway. And you definitley wont get 0 marks. You knew to integrate which gets you a mark.
(Original post by Livesindreams)
I've gone over what you said earlier so if you don't want to see don't but I reckon it might reassure you. I'd estimate you've only lost 7 marks in all those questions.
In Q21a) I got the wrong midpoint, but I kept working through and got the answer to be 6x+11y=152. Would I get any marks at all? (3)
We've been told it's a carried through error so you lose one mark when you originally make the mistake and then if you work it through with your mistake correctly you don't loose any marks so providing you did the rest using the right method - (2)
21c) I guessed it to be BT:TQ = 2:1. But because I got the wrong midpoint and so wrong value of Q I would have lost the marks, but I did show how I would have got it if I had the right point. So again any marks? (2)
Not totally sure what you mean but think you mean you only did it wrong because of your incorrect midpoint? If so, as you were already penalised for that (2)
23b) I couldn't get what x and y were, yeah I know silly mistakes. So I made up some values, x=4 and y=1. And then got sinb=1/root17 and cosb=4/root17. So any marks there? (4)
Was this the one where part a asked for the values? If so, another carried through error and so (4)
c)i) Because of my mistake in b, I messed this one up as well. And got sin(a-b)= 10/root15root17 (2)
ii) Got sin(b-a)= -10/root15root17, so again, any marks in these questions? (2)
Providing you got this wrong because of your earlier mistake and did the correct method. (4)
2b)ii) I put down that the min/max for cos= 0. Again stupid mistake, but carried it through like you normally would and got max=67.4 and min= 247.4. (2)
Not sure about this but I reckon you'd just lose a mark for your mistake and then they carry it through. (1)
3b) I wrote down the radius of the larger circle as root72 and the centre of it to be (-7,-2) (6)
Don't get what you mean about this sorry. Can't work out how many you'd get.
5b) For some reason, I gave the equation and extra x and so made it;
A(x)=x(12x-2x^3) = 12x^2-2x^4. But I worked this out normally and got the max value to be root3. (6)
If you did what I think then they'd just count that as copying the question down wrong so another carried through error (5)
6c) I screwed this up badly, but I knew to integrate but used A and 0 as the limits, to get 47/3 units^2. (I made my A=5)(7)
This doesn't sound quite so good. You'd get a mark for knowing to integrate and integrating correctly at least. And if you got A wrong in a previous part you'd get a mark for the limits in this question too. (3)
NOTE: I'm presuming you've done everything right for your numbers which I'm sure you will have.