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# OCR (not MEI) Core 3 - 19/01/2011 Watch

1. (Original post by mathsgeek101)
What did everybody get for that horrible transformation of -4f(x+3) - question 2?
Translate by 3 to the left.
Stretch by 4 vertically.
Then reflect vertically.

Stationary points were (-3,0) and (-5,24) I think?

I still think I got the sketch wrong. I spent 10 mins on that.
2. (Original post by mathsgeek101)
What did everybody get for that horrible transformation of -4f(x+3) - question 2?
one coordinate was (-24, -5) or something?!?

what did people get for the iteration one?? and the q8.. all the function ones
3. Just saw that the paper was uploaded, so had a crack at the first page. I'm not sure how correct it is since I did it in 5 minutes and have no calculator (being borrowed by current students ) so answers are either done in my head or in exact form:

1) x = 3a, x = a/3

2) sketch; move 3 to left and multiply entire function by -4 (by stretching and reflecting)

3) 14400pi = 45000cm^2 (2 sf)

4i) R = 25, a = sin-1(7/25) (no calc sorry )

ii) theta = sin-1 (12/15) - a (alpha from part i)

5) a = 9

volume = pi x (12ln25) = 12pi ln25

Shall I do the rest of them for you too?
4. First question i got x=a/3, for question 4 ii) did anyone get 12.4 for the angle. Volumes of revolution i got 2pi ln25, and 2 hundred and something over 3 hundred and something for question 8 6 marker. Cant remember exactly what i put for question 9 but think its wrong..
5. (Original post by mathsgeek101)
What did everybody get for that horrible transformation of -4f(x+3) - question 2?
multiply the Y coordinates by -4
and take 3 off the x coordinates
then draw and replot

so its a translation by 3 units in the negative x direction then reflection in the x axis
6. (Original post by mathsgeek101)
What did everybody get for that horrible transformation of -4f(x+3) - question 2?

trans: negative x dir, 3
reflection: upside down
stretch: y factor 4. (= y value x4)

I hope that's the right answer lol

====

Anyone got the answer for Q1? I know it's strange to ask that...

(edit: I got something like a/3 and can't get rid of the a)
7. (Original post by trix909)
Damn, well thats 2 marks down the drain, prob would of got one mark for doing a relevant method.

Nononononono

You need to solve for X not a ,

here is the paper look at the answer

http://www.thestudentroom.co.uk/atta...7&d=1295452716
8. (Original post by Glen_Nichols)
My y coordinate was 24 and x...........something like -8 (for the stationary points)
Me too
9. Here are some answers 1-5. Not going to draw graph though. Hopefully will put some minds at ease.
1.x=a/3

2. Graph

3. 45000

4.i) 25sin(x+16.3)
ii)x=12.4 and 135.1

5. a=9
Volume of revolution=12(pi)ln(25)

Will post rest in next few minutes
10. (Original post by gildartz)
anyone get x&gt;(ln3)/4 for the last question, part ii I think
Yep

What did people get for that question that said cosec(a)=cosec(b)?

I said b= 2pi + a

I didn't get what it was going on about.
11. and a strech in the y by 4 :P
12. that was a real biatch of a paper
13. [QUOTE=asabashoyuki;29461349]trans: negative x dir, 3
turned the graph upside down
stretch: y factor 4. (= y value x4)

I hope that's the right answer lol

====

stationary point were,

5,24

and 3.0

what did you lot get?
14. (Original post by yourworstnightmare)
Just saw that the paper was uploaded, so had a crack at the first page. I'm not sure how correct it is since I did it in 5 minutes and have no calculator (being borrowed by current students ) so answers are either done in my head or in exact form:

1) a = 3

2) sketch; move 3 to left and multiply entire function by -4

3) 14400pi = 45000cm^2 (2 sf)

4i) R = 25, a = sin-1(7/25) (no calc sorry )

ii) theta = sin-1 (12/15) - a (alpha from part i)

5) a = 9

volume = pi x (12ln25) = 12pi ln25

Shall I do the rest of them for you too?
There's another answer for the first Q
15. [QUOTE=scaredoftests;29461395]
(Original post by asabashoyuki)
trans: negative x dir, 3
turned the graph upside down
stretch: y factor 4. (= y value x4)

I hope that's the right answer lol

====

stationary point were,

5,24

and -3.0

what did you lot get?
that is meant to be -3,0
16. definatitelyyyyy an EPIC fail!!!..
ironically its good to know that every1 on average did bad

ave lost 25 markss and that doesnt include the ones that i think i got right.....(if it makes any1 feel better)
WHERES MR M 2 PUT ME OUT OF MISERYY.??
OHH DEARR
17. (Original post by nomzie)
definatitelyyyyy an EPIC fail!!!..
ironically its good to know that every1 on average did bad

ave lost 25 markss and that doesnt include the ones that i think i got right.....(if it makes any1 feel better)
WHERES MR M 2 PUT ME OUT OF MISERYY.??
OHH DEARR
Calm down, I'm sure grade boundaries will be rock bottom. If it makes you feel better i've probably lost atleast 15 too.
18. (Original post by nikita_atikin)
Yep

What did people get for that question that said cosec(a)=cosec(b)?

I said b= 2pi + a

I didn't get what it was going on about.
I got b = 3pi - a
19. (Original post by Glen_Nichols)
There's another answer for the first Q
I haven't gone back and solved for x, I thought it asked for the value of a, silly me
20. [QUOTE=scaredoftests;29461412]
(Original post by scaredoftests)

that is meant to be -3,0
and also,its meant to be (-5,24) not (5,24) for the coordinate

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