C4 Jan 12 Edexcel Post Exam Discussion - Solutions in first post

Original post by asas78978

yes as t--->+infinity , e^-1/3t tend toward 0. therefore P=5/1+0 =5 in thousand so 5000. :smile:

but i dint show the equation. is that still fine?

Reply 382

Ruvermillion

1

for the parametric question, how many marks will i lose if i didn't differentiate x? I know that means i got the entire part b wrong and the whole thing altogether was worth 8 marks :s

Reply 383

Original post by Ruvermillion

for the parametric question, how many marks will i lose if i didn't differentiate x? I know that means i got the entire part b wrong and the whole thing altogether was worth 8 marks :s

method mark for not differentiating and all the other accuracy marks provided your method was correct. I'd say, you would lose around 4 to 5 here.

Reply 384

Erotas

For 6c, I kept getting to 4ln(1+cosx) -4(1+cos)x + k just like it is in the mark scheme.......
but the question says 4ln(1+cosx) - 4cosx + k
Confused much!

Reply 385

aaronbenham

Original post by Erotas

For 6c, I kept getting to 4ln(1+cosx) -4(1+cos)x + k just like it is in the mark scheme.......
but the question says 4ln(1+cosx) - 4cosx + k
Confused much!

If you just expand to make 4ln(1+cosx) -4cosx -4 +c
You can then take the -4 into the c, as they are both just constants. Rename k as c, and then k=c-4

Hope this makes sense :biggrin:

Reply 386

asas78978

Original post by vishcr7

but i dint show the equation. is that still fine?

Well I suppose it is fine as long as you said something like exponential function tend towards 0 and then 5/1 in thousand=5000. :smile:

Reply 387

OP

Original post by vishcr7

i did the modulus method, removed it to get 109 directly, then removed it again to get 71 or something to subtract it from 180. great. so no marks at all, or a couple to get the final answer right and the formula?

also, q8c- e^infinite is not possible and e^-infinite=0, therefore population can never exceed 5000, would give me the mark?

You should be okay on the first one, they don't tend to be too picky

I would say no to the second one, but you never know.

Reply 388

OP

Original post by gdunne42

the day before results

I seem to remember getting them the week before the jan results, last year

Reply 389

otrivine

14

Original post by Arsey

I seem to remember getting them the week before the jan results, last year

HI MATE i sent a message on s1 please check if possible i would really appreciate :smile:

Reply 390

GreenKitten

6

Dang... I put 1/3pi ln4... still the same as 2/3 pi ln2 though! Aah, it's probably just one little mark, so here's hoping you don't need all 75 marks to get 100 UMS!

(edited 12 years ago)

Reply 391

Original post by Arsey

I seem to remember getting them the week before the jan results, last year

please post it here as soon as you get it, for c3 and m1 all the others too..

Reply 392

Original post by GreenKitten

Dang... I put 1/3pi ln4... still the same as 2/3 pi ln2 though! Aah, it's probably just one little mark, so here's hoping you don't need all 75 marks to get 100 UMS!

nope, its still in the frm of klna, so you're not losing anything. If that was th only error you made, according to you, you'll definitely get a 100.

Reply 393

Original post by asas78978

Well I suppose it is fine as long as you said something like exponential function tend towards 0 and then 5/1 in thousand=5000. :smile:

arsey has a different opinion on this though. but thanks :smile:

Reply 394

asas78978

Original post by vishcr7

arsey has a different opinion on this though. but thanks :smile:

What is his opinion? Surely it works! :s-smilie:

Reply 395

gdunne42

21

Original post by Arsey

I seem to remember getting them the week before the jan results, last year

was that from the emporium email? I don't think I saw them on the Edexcel site that early - may be wrong

Reply 396

OP

Original post by asas78978

What is his opinion? Surely it works! :s-smilie:

It is only a 1 marker, so you could be okay, it just isn't a complete explanation that is all.

Reply 397

OP

Original post by gdunne42

was that from the emporium email? I don't think I saw them on the Edexcel site that early - may be wrong

I never get anything direct from the Edexcel site

Grade boundaries will be set at the end of Feb. We get the MS at least a week before the results are released. I can not remember if we get the grade boundaries at the same time, it may not be until the day before the results are released.

Reply 398

Original post by asas78978

What is his opinion? Surely it works! :s-smilie:

i hope it does, but he feels that unless ive expressed it IN the equation, i'll get 0 for it.

Reply 399