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OCR (not MEI) C2 - Wednesday 20th May 2015

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Reply 440

username1424683

Original post by Lil_timmi

ImageUploadedByStudent Room1432135522.206627.jpg

This is how I answered 7. iii)

Can someone tell me where I went wrong???

Posted from TSR Mobile

This is how I did it :smile:

ImageUploadedByStudent Room1432136554.453466.jpg

La vie? C'est la vie.

Reply 441

study101

would I lose a mark if I didn't put dx after the integral in the double differential thing?

Reply 442

chrisceng

I think I have made some mistakes on question 3 where I can't remember if I have used cosine rule at all... Can someone show me how to get the correct answer for question 3 please?

(edited 8 years ago)

Reply 443

andygeor

Original post by study101

would I lose a mark if I didn't put dx after the integral in the double differential thing?

dont think you would

Reply 444

study101

Original post by andygeor

dont think you would

okay I hope I don't :/ thank you!

Reply 445

ayl21

I thought you took it from 6pi as the graph is stretched by a scale factor of 3 unless I'm wrong, but now I am unsure :frown:

Reply 446

andygeor

Original post by ayl21

I thought you took it from 6pi as the graph is stretched by a scale factor of 3 unless I'm wrong, but now I am unsure :frown:

tan graph isnt symmetrical so can't take from 6pi. as they repeat every 180 degrees or pi radians with just normal tan(x) so you need to add on 3pi radians to the first value because its tan(1/3 x)

Reply 447

nurav11

Original post by sarahowl

Haha I did this too, the panic of exams does some very strange things...

Original post by jamesplay73

I know yea haha, I just had no time left thank you anyway :smile:

Hahah ok fair enough, at least you guys didnt write the wrong answer, that's all that matters :smile:

Reply 448

Mrrexxxx

Your marks add up to a today of 74, I am pretty sure the N=24 question was worth 4 marks

Reply 449

ayl21

Original post by andygeor

tan graph isnt symmetrical so can't take from 6pi. as they repeat every 180 degrees or pi radians with just normal tan(x) so you need to add on 3pi radians to the first value because its tan(1/3 x)

I didn't use the tan graph, I squared both sides instead and used the cos graph

Reply 450

ChoccyPhilly

last answers were 3.32 and 15.5, anyone?

Reply 451

Lil_timmi

I understand how to solve it using tan, I'm just trying to see where my second answer of 6.1 rad comes from... I'm kinda frustrated at how I've lost so many marks because I didn't notice that you could use tan

Thanks everyone for the help though

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(edited 8 years ago)

Reply 452

ayl21

Original post by ChoccyPhilly

last answers were 3.32 and 15.5, anyone?

Yeah I got something along those lines, how did you get the 15.5 answer?

Reply 453

andygeor

Original post by ayl21

I didn't use the tan graph, I squared both sides instead and used the cos graph

i think (or what i did anyway) what you had to do was divide both sides by cos(1/3 x) and get 2=tan(1/3 x). not sure if it'd give the correct answers to square both sides but i may be wrong

Reply 454

nurav11

Original post by arabinthemist

Used my fp1 knowledge for that question :P. I thought it was a paper that required you to be careful, but otherwise was quite straight forward. I know i've lost all my marks on the last question cus of radians smh

Yeh should have done that :/. I tried to insert N as a which is why it all went to hell but yeh, because the steps were right, just with completely the wrong numbers and idea, I think I may scrape a couple of marks there which would make the difference. Rest of straightforward so long as you checked well. What did you do for the last question? Answered it all in terms of degrees?