OCR (not OCR MEI) Core 3 answers Jan 2011

Reply 20

DaveGBG

Original post by Mr M

Oops! Anyone know how I can change the thread title to include Core 3?

You can change it by cliking edit on the opening post and changing it in the title box there :smile:

(P.s- any chance of your working for question 8bii ? )

Reply 21

stitch48

4

Ah well. This is why everyone says C3 is the hardest. See you again in six months c3. :biggrin:

Reply 22

purplestarfish

Original post by Mr M

I used Autograph to do it using Simpson's Rule with 4 strips - it is possible that Autograph can't round properly! I will check it by hand after I have something to eat.

how many marks would 3a = x, get for the first question? without further simplification

Reply 23

nomzie

Original post by Mr M

I used Autograph to do it using Simpson's Rule with 4 strips - it is possible that Autograph can't round properly! I will check it by hand after I have something to eat.

MR M
i am pretty sure i got 42/72.......i did differentiate anything that needed differetiation on questionn 9.....
WHAT GRADE DO YOU THINK AM LOOKING @?.....i know it cant be that good though

thank you for answerss btw!

Reply 24

I0144

Original post by Mr M

OCR (not OCR MEI) CORE 3 answers Jan 2011

ii)

y \geq 2 \sqrt k

(5 marks)

~~What did you get for your x value~~

\frac {2k }{\sqrt k }

is the same as

2 \sqrt k

(edited 13 years ago)

Reply 25

awlright

1

How do you reckon this paper matched up to last june's Mr. M :biggrin:

Do you reckon we could be looking at another 50/72 A boundary ? :smile:

Reply 26

Steeeee

Mr M, how many method marks do you think i could possibly get for question 5 providing i got the wrong value for a? I got the correct integral and used the method for finding the volume correctly. 3-4?

OP

Original post by Revolution is my Name

Are you sure about that one? I got 20.3, and so did everybody else who posted their answer on t'other thread.
Also, what raw mark would you say would be necessary for full UMS?

doing it by hand gives 20.26282929... so yes 20.3 is right.

OP

Original post by DaveGBG

Thanks so much Mr M, I did better than I imagined, looking at 56-60 :biggrin:

Any chance you could show your workings for 8b ii) ? The horrible tan one? :smile:

\frac{1}{4} \times \frac{15}{8} \times \frac{240}{161}

OP

Original post by Steeeee

Mr M, how many method marks do you think i could possibly get for question 5 providing i got the wrong value for a? I got the correct integral and used the method for finding the volume correctly. 3-4?

More than that if you did the rest right - maybe 6?

OP

Original post by awlright

How do you reckon this paper matched up to last june's Mr. M :biggrin:

Do you reckon we could be looking at another 50/72 A boundary ? :smile:

I can't remember last year now but that was quite difficult - I would be surprised if the boundary was that low however.

Reply 31

CitizensUnited

1

Original post by Mr M

ii)

\beta = 3\pi - \alpha

(2 marks)

I left it as

\mathrm{cosec}\ \alpha + \mathrm{cosec}\ \beta = 3\pi

- will I drop one mark or all two?

(edited 13 years ago)

OP

Original post by nomzie

MR M
i am pretty sure i got 42/72.......i did differentiate anything that needed differetiation on questionn 9.....
WHAT GRADE DO YOU THINK AM LOOKING @?.....i know it cant be that good though

thank you for answerss btw!

mid to high C?

OP

Original post by purplestarfish

how many marks would 3a = x, get for the first question? without further simplification

That isn't right so maybe 1 if you are lucky.

Reply 34

J DOT A

Original post by Mr M

That isn't right so maybe 1 if you are lucky.

Ahh okay thanks! stupid stupid mistake.
Okay, now for the killer question.... I used tan2(theta)=2tanA/1-Tan^2A
Therefore, I did Tan4a=2tan2A/1-tan^2A.
I got the correct tanx and cotx values, however I accidently subbed in tanx=1/4 in my tan4a equation, getting so I ended up with 2*2*1/4 divided by 1-2*1/4^2
and got something like 5/something
How many marks would I have lost for that question?

Reply 35

thetaxman123

Wow overall this went better than expected. I think i got it all right apart from not putting the y co-ord for 6ii (how many marks will I lose for this) and I think i may have messed up the simpson's rule although im unsure . Anyway thanks Mr.M as always and i'm glad you said C3 was the hardest so far this session. Good luck everyone and by the way, what's the date in march for the results.

OP

Original post by gildartz

Hi Mr M.
Thanks a lot for the answers, for question 8)a)i), if you only drew 1 positive U and 1 negtaive U, how many marks do you think I would lose?

1 if the two bumps you drew were correct

Reply 37

Dunney101

Original post by Mr M

question 5 is fine and I think it asked for the coordinate in 6ii - I will check if I can work out how to bring the paper back up on my screen!

Thanks for your reply, i think i know what i have done i only wrote the x coordinate for P. How many mark do you think i will drop? it was out of 5?
Thanks.

(edited 13 years ago)

Reply 38

tpowertj

How many UMS do you think 58/72 would be?