You are Here: Home >< Maths

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

1. i found that gf(x)= (lnx)^2 + 8 so gf'(x)= 1/x^2 therefore it equals 1/e^3
I differentiated (lnx)^2 differently cause it was in brackets, so mine came out at 2x1/x(lnx).
2. (Original post by jayjay1)
how did everone expand tanacotatan2a?
It was TanXCot2XTan4X and if you take each individual part and work it out by subbing in TanX=1/4 then you get the answer. It was long though.
3. (Original post by DaveGBG)
Anyone else have a time issue with this paper?
I did, got to the end with about a minute to spare...then realised there was a question 9.

Not that it mattered - I couldn't do it anyway, I just quickly differentiated f(x) in the hope of getting a method mark.
4. (Original post by jayjay1)
how did everone expand tanacotatan2a?
I used cot x = 1 / tan x , then did the tan 2x expansion, cancelled and substituted tan x for 1/4 , then simplified evverything. I think I got 225/384 or something.
5. Worst exam I have ever sat in my life!
only confident with the 1 mark question, 'tan2a'
6. (Original post by CitizensUnited)
I used cot x = 1 / tan x , then did the tan 2x expansion, cancelled and substituted tan x for 1/4 , then simplified evverything. I think I got 225/384 or something.
hey i did the same as you but i got 32/135
anyway hope i get marks for method
7. (Original post by jackdelderfield)
I differentiated (lnx)^2 differently cause it was in brackets, so mine came out at 2x1/x(lnx).
i wasnt sure how to differentiate it, so i used the product rule with both u and v = to lnx, making (lnx)^2 and got something like 2(lnx)/x
8. (Original post by DaveGBG)
Anyone else have a time issue with this paper?
Yes majorly! i had like 5 mins to do question 9.ii) 9.iii) i was panicing so much that i just differentiate the fucntion and basically left the last 9.iii) . I couldnt even comprehend what to do once i differentiated lol i think just on question 9 i lost 10 marks. cool
9. whers mr M with the answers
10. For the tan(theta) question => cot(theta)=4 tan(theta)=1/4

tan*(1-tan^2(theta)/2tan(theta))*(2tan(2theta)/1-tan(2theta))

I did inverse tan on tan(theta)=1/4 to get theta to get 0.244... since we've got 2theta as well I did (theta)*2=0.4899 then I did tan(2theta)=>tan(0.4899) =8/15

So you have tan(theta)=1/4 and tan(2theta)=8/15
and put it back into the equation to get
225/322 I think. Am I right?
11. (Original post by godexists1234)
i wasnt sure how to differentiate it, so i used the product rule with both u and v = to lnx, making (lnx)^2 and got something like 2(lnx)/x
Interesting. Substituting e^3 seems to give the same answer from both, 6/e^3?
12. Let's just say that C3 and I will be meeting again in June. :\
13. (Original post by Jin3011)
For the tan(theta) question =&gt; cot(theta)=4 tan(theta)=1/4

tan*(1-tan^2(theta)/2tan(theta))*(2tan(2theta)/1-tan(2theta))

I did inverse tan on tan(theta)=1/4 to get theta to get 0.244... since we've got 2theta as well I did (theta)*2=0.4899 then I did tan(2theta)=&gt;tan(0.4899) =8/15

So you have tan(theta)=1/4 and tan(2theta)=8/15
and put it back into the equation to get
225/322 I think. Am I right?
14. every1 how did you find this paper overall on a scale of 1-10 with 1 being the easiest and 10 the hardest!
15. (Original post by ElMoro)
16. (Original post by I0144)
Not sure whether these are right, relooked at the hard questions at home and i've got these.

1) x = a/3 and -3a
2) Two stationary points are (-3,0) and (-5,24)
3) 45000
4i) 25Sin(theta+16.3)
ii) theta= 12.4 and 135
5) 12(pi)ln25
6ii) 2.398
7i) x = (e^8-8)^0.5
ii) e^x
iii) 6/e^3
iv) 20.3
8aii) 3pi-alpha
bii) 225/322
9ia) f'(x) = 2(e^2x+3/e^2x); therefore e^2x > 0; so f'(x) > 0
b) x > ln3/4
ii) Range of g(x) >= k^0.5 (1-k)

So much easier when you do it at home...
For The Last One Im Pretty Sure Its 2rootk
Apart From That Im Sure They Are Right
17. (Original post by Flint_09)
every1 how did you find this paper overall on a scale of 1-10 with 1 being the easiest and 10 the hardest!
Not sure tbh, doing it at home now seems much easier than in the exam hall.
But on first sight, and comparing to previous papers, I'd say 7+ln(e^1/2)/10
18. (Original post by Flint_09)
every1 how did you find this paper overall on a scale of 1-10 with 1 being the easiest and 10 the hardest!
8/9
19. (Original post by Flint_09)
every1 how did you find this paper overall on a scale of 1-10 with 1 being the easiest and 10 the hardest!
Without including question 9, i would give it 7-8 out of 10. Including question 9 i would say 10.
20. Question 9 was really really quite hard. Especially the last question worth 5.

I'm hoping I have got around 62 on the paper... might get lucky and get an A* but I have a feeling that's an A.

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: January 23, 2011
Today on TSR

### Oxford grad sues for £1m

Claims damages because he didn't get a first

### 'No evidence of shots fired' at Oxford Circus

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

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.