OCR Core 3 (Not MEI) - Wednesday 20th January PM

mrdude

I made the silly mistake of assuming tan5 is two times tan10 - so thats how I worked out my answer. Would I get any method marks at all, or would all marks be lost?

That is just wrong so no marks there.

Reply 381

*MJ*

OP

2

Mr M

8 cos \theta cosec ^2 \theta = 3

Ahh, now I remember, it was the one where cos theta = -3 is undefined, right?

I got it correct. :smile:

Thanks for posting.

*MJ*

Ahh, now I remember, it was the one where cos theta = -3 is undefined, right?

yes

Reply 383

lrn2physics

4

What was question 2 i again Mr M? By the way, you aren't Mr. Meyers are you? :P

lrn2physics

What was question 2 i again Mr M? By the way, you aren't Mr. Meyers are you? :P

6 \sin 2 \theta = 5 \cos \theta

... and no.

Reply 385

The_wise

1

Mr M

\int^{\ln 4}_0 (ke^{3x} + (k-2) e^{-0.5x}) \ dx = 185

Mr M, can you please quickly tell me how to work this question out, step by step please :P lol thanks x

The_wise

Mr M, can you please quickly tell me how to work this question out, step by step please :P lol thanks x

Maybe later. Someone else might go through it with you now. I have 5 lessons to plan for tomorrow!

Reply 387

payday5950

this paper was a joke. I averaged 95% on the past papers from 2005 through to June 2009 and was honestly expecting an A*. I did Core 4 last week which was piss compared to this. I'm looking at a marginal A I reckon but more likely a B. THere's still hope lol, If I got 100 in C4 I'll only need 80 in C3 for an A* - long shot - but possible nonetheless.

Reply 388

mrdude

Mr M

That is just wrong so no marks there.

Ah thought so, I could have lost anything in between 12 and 18 marks, depends on method marks etc. Fingers crossed for an A :wink:

Reply 389

The_wise

1

payday5950

this paper was a joke. I averaged 95% on the past papers from 2005 through to June 2009 and was honestly expecting an A*. I did Core 4 last week which was piss compared to this. I'm looking at a marginal A I reckon but more likely a B. THere's still hope lol, If I got 100 in C4 I'll only need 80 in C3 for an A* - long shot - but possible nonetheless.

Really?? I thought to get an A* in OCR maths this year you had to get an A* in C3 and C4, thats what our head of maths told us?

Reply 390

The_wise

1

Mr M

Maybe later. Someone else might go through it with you now. I have 5 lessons to plan for tomorrow!

No worries, thanks anyway.

Can anyone else who has done it correctly please explain how you do this question please? xxx

Reply 391

lrn2physics

4

The_wise

Mr M, can you please quickly tell me how to work this question out, step by step please :P lol thanks x

Bro, expand it.
ke^(3x) + k e^(-0.5x) -2e^(-0.5x)

Integrate it.

1/3 k e^(3x) -2ke^(-0.5x) + 4e^(-0.5x)
from 0 to ln4

That gives you

(64/3 k - k + 2) - (k/3 -2k + 4)

so,
22k -2 = 185
k = 8.5

Reply 392

payday5950

The_wise

Really?? I thought to get an A* in OCR maths this year you had to get an A* in C3 and C4, thats what our head of maths told us?

I thought that initially but the ocr documentation says you have to average 90 UMS over C3 and C4 which not only means you can get lower than 90% and still get an A* (if boundaries are low for example) , it also means you technically don't have to get 90 UMS in both. so your looking for 180 UMS over the two.

Reply 393

The_wise

1

lrn2physics

Bro, expand it.
ke^(3x) + k e^(-0.5x) -2e^(-0.5x)

Integrate it.

1/3 k e^(3x) -2ke^(-0.5x) + 4e^(-0.5x)
from 0 to ln4

That gives you

(64/3 k - k + 2) - (k/3 -2k + 4)

so,
22k -2 = 185
k = 8.5

ahhh no

i didnt expand it but integrated straight away, and i didnt get the right answer? do you think i will get any method marks? also is it not possible to integrate without expanding? if it possible, then can you please tell me what the integral would be to see if it is similar to mine? x

ahh no :frown:

Reply 394

Esdri

Thanks alot for all the answers and help you've been posting Mr M, god knows you didn't have to ^^

Reply 395

Pari92

O-J-Hick

Overall I thought this was a relatively straightforward paper and will clearly separate the men from the boys. Looking through the answers I think I have got between 67 to 70 out of 72. Hopefully the grade boundarues are not ridiculously high and you need 71 for an A teeheehee

yes same here :smile:

Relatively speaking, it required more thinking than other c3 papers have done in past but I'm expecting about 69/70 out of 72.. Can't believe I forgot +c in the 1st question!

Reply 396

The_wise

1

payday5950

I thought that initially but the ocr documentation says you have to average 90 UMS over C3 and C4 which not only means you can get lower than 90% and still get an A* (if boundaries are low for example) , it also means you technically don't have to get 90 UMS in both. so your looking for 180 UMS over the two.

oh right.. thats new and GOOD news for me :biggrin:

you got the link for this document plsss????!!

Reply 397

member348400

The_wise

ahhh no

i didnt expand it but integrated straight away, and i didnt get the right answer? do you think i will get any method marks? also is it no possible to integrate without expanding?

ahh no :frown:

I integrated without expanding and got 8.5

You get 1/3ke^3x -2(k-2)e^-0.5x

That's without limits obviously.

Reply 398

lrn2physics

4

The_wise

ahhh no

i didnt expand it but integrated straight away, and i didnt get the right answer? do you think i will get any method marks? also is it no possible to integrate without expanding?

ahh no :frown:

Yeah, you can. It should give you the same answer. If you integrated it right, you should get the method mark.

Reply 399

MathsHamster

10

Mr. Cricket

What is the 8.5 thing about?!?
Was that the ammount the radius was increasing with respect to time?
If so i got it horribly wrong (1.6) lol

Question 9ii) totally fudged it up
Qu 9iii) worked along the right lines, but made a stupid mistake meaning i didnt get the correct answer.

Also the graph translation question was -1.5 in x-direction.
I stupidly put -3 in x-direction!

Was definitely a harder than average paper, but I found it okay - hoping for any A :smile:

x

8.5 was the question with k.
I got 1.6 on the one about the oil spill :smile:

OCR Core 3 (Not MEI) - Wednesday 20th January PM

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