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# C3 OCR (Not MEI) June 13th Tweet

Maths exam discussion - share revision tips in preparation for GCSE, A Level and other maths exams and discuss how they went afterwards.

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1. Re: C3 OCR (Not MEI) June 13th
Hardest C3 paper ever!?!?!
I did about a million C3 papers in prep for this, and none of them was anything like this! D:

I really hope C4 is better (yn)
2. Re: C3 OCR (Not MEI) June 13th
(Original post by charlielower)
to show p=10/3....you know that gradient at P and gradient of tangent of curve are equal therefore equate the differentials of the curve to the line OP....the line OP intersects the origin (has y intercept 0) therefore takes the form y=ax

equating differentials means a= expression for differential of curve, then manipulate to find value of a at x=10/3

you then know the equation on OP and then just a case of taking integral from area of rectangle that P makes with x and y axis

I didn't like the last page, (i) I seemed to end up with 2tan(theta)
I ended with 2tan(theta) aswell, amongst other things,
"you then know the equation on OP and then just a case of taking integral from area of rectangle that P makes with x and y axis"
if you mean to find the area, you want the area of triangle OP-integral
3. Re: C3 OCR (Not MEI) June 13th
(Original post by Mousebudden)
To find the area of the shaded region

Did anyone else do this:

Find area underneath tangent using [(10/3)*(5)^0.5] divide by 2.. (using same method as area of triangle

and then use integration to find area of 'non shaded region'

subtract area of non shaded region from area of triangle to get area of shaded region
**** thats a really good point, I feel like an idiot now, I integrated the equation of the STRAIGHT LINE to find the area, what the hell was I thinking, no wonder it took me a while :/
4. Re: C3 OCR (Not MEI) June 13th
(Original post by R0BMAN)
Yeh the limits for the tangent were 10/3 and zero, and the limits for the curve were 10/3 and 5/3. That what you mean?

Also for the equation of the tangent did everyone get something like 300/36root5 after you put the limits in? Before it was like, y = 3x/4root5 or something like that? Struggling to remember what I put....
AHHH! I'm such an idiot... seems so easy now..
5. Re: C3 OCR (Not MEI) June 13th
How many people eneded up with 2tanTheta instead of tanTheta
6. Re: C3 OCR (Not MEI) June 13th
yeah I ended up with (5Root5)/9 .. or something along those lines?
7. Re: C3 OCR (Not MEI) June 13th
Can anyone remember what all the questions were? I can't; something like:
1) Integration
2)
3)Translations & transformtions
4)
5)
6)Area under a curve
7)
8)exponential functions
9)trigonometrical identities
8. Re: C3 OCR (Not MEI) June 13th
That was really hard imo... Also couldn't prove P=10/3, kept ending up with -10/3 and checked it several times before I gave up on it... The area for that question as well... It came out really weird, so I'm guessing I've probably lost all the marks on that...

Also had trouble rearranging the long equation to equal tan x (or theta w/e w/e)...

Ugh that was so horrible. GOODBYE UNI 2011!!!
9. Re: C3 OCR (Not MEI) June 13th
(Original post by geojenks)
Can anyone remember what all the questions were? I can't; something like:
1) Integration
2)
3)Translations & transformtions
4)
5)
6)Area under a curve
7)
8)exponential functions
9)trigonometrical identities
7 - functions of f, g and h.
5 - differentiation - d2y/dx2
10. Re: C3 OCR (Not MEI) June 13th
(Original post by XST)
I thought it was the hardest C3 yet. Didn't really know how to do that exponential one where you had to show that T was a root. For question 9, I couldn't for the life of me find the area...I got the integral (2/9)(3x-5)^(3/2) but one of the limits was 0 right, so surely you would get the square root of a minus number? :/
i think you mean the 9 mark question not question 9 :P to find the area you find the area under the curve: limits being 5/3 and 10/3 then find the triangle area and take the area under the curve away from that if that makes sense, you got the right integral (Y)
but yeah i couldnt do that find root of e^kt = c question either, and my question 9 was a fail..
11. Re: C3 OCR (Not MEI) June 13th
(Original post by geojenks)
Can anyone remember what all the questions were? I can't; something like:
1) Integration
2)
3)Translations & transformtions
4) Modulus?
5) Differentiation twice?
6)Area under a curve
7) Functions?
8)exponential functions
9)trigonometrical identities
Jeez cant remember. Can remember the mod one although it was the one I didnt have time to check.
Last edited by R0BMAN; 13-06-2011 at 11:32.
12. Re: C3 OCR (Not MEI) June 13th
(Original post by Mousebudden)
How many people eneded up with 2tanTheta instead of tanTheta
I got tantheta,

after using all the product rules I got something like this,

sintheta(cosalpha+3)
---------------------------- = tantheta
costheta(cosalpha+3
13. Re: C3 OCR (Not MEI) June 13th
(Original post by geojenks)
I ended with 2tan(theta) aswell, amongst other things,
"you then know the equation on OP and then just a case of taking integral from area of rectangle that P makes with x and y axis"
if you mean to find the area, you want the area of triangle OP-integral
yeah we both mean the same thing everyone I spoke to after the exam said they got 2tan(theta).....HAVE OCR MADE ANOTHER MISTAKE IN EXAMS?

going by everyone's reactions, the paper was very hard, so I think boundaries may be dropped to 55ish for an A?
14. Re: C3 OCR (Not MEI) June 13th
Who managed to prove P=10/3 ? Everyone I talked to said they couldn't prove it -_-
15. Re: C3 OCR (Not MEI) June 13th
(Original post by XST)
I got tantheta,

after using all the product rules I got something like this,

sintheta(cosalpha+3)
---------------------------- = tantheta
costheta(cosalpha+3

Yeh thats what I got.

Then the very last one.... was a bit confusing but I ended up with (tan^-1k)/6 which is what I hope they meant.
16. Re: C3 OCR (Not MEI) June 13th
Worst C3 paper of the century... Past papers are almost useless for this paper lol. Thanks OCR, goodbye university.
17. Re: C3 OCR (Not MEI) June 13th
what did everyone get for the transformation equation...y=-ln(x/3)+4 ?

I nearly put the 4 in the brackets, but it said 4 units in y direction not x direction
18. Re: C3 OCR (Not MEI) June 13th
that would be nice.
does anyone remember getting an answer
(4x^2-6x)
------------
(4x-3)^2
I remember thinking i ought to simplify but couldnt, i think it might have to the one where it asked for d^2y/dx^2
19. Re: C3 OCR (Not MEI) June 13th
(Original post by charlielower)
what did everyone get for the transformation equation...y=-ln(x/3)+4 ?

I nearly put the 4 in the brackets, but it said 4 units in y direction not x direction
I got ln(4/x^3)

It was lnx

-lnx

-3lnx

-3lnx + ln4

= ln(4/X^3)

Im pretty sure it said + ln4, I went back and checked this one and I had originally put 4 but it said move parallel to the y axis by ln4, not 4.
20. Re: C3 OCR (Not MEI) June 13th
(Original post by geojenks)
Can anyone remember what all the questions were? I can't; something like:
1) Integration
2)
3)Translations & transformtions
4)urrr i think it was that question with the find cosalpha and secbeta
5)differentiating with product rule and quotient rule
6)Area under a curve
7)functions
8)exponential functions
9)trigonometrical identities
cant remember 2...
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