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2016 May 25th Edexcel Core 2 Questions and answers. [Unofficial mark scheme] 2016

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Original post by medapplicant2016
That's what I thought, I did get 16.something though, and did work out f"(x) > 0, which usually gives you 2 marks (you don't need to sub)

If you got 16.6 then i think you may only lose 1 mark then just for not subbing for the minimum value
Original post by dididid
the answer was b= (3a+5)/9


I did this

log 3 (3b+1/a-2) = -1
3^-1 = 3b+1/a-2
1/3= 3b+1/a-2
a-2=9b+3
a-5=9b
b=a-5/9
Original post by tory88
Is question 6 written out correctly? I get 11π30\frac{11\pi}{30}or 31π30\frac{31\pi}{30}

EDIT: Seen that there have been amendments since then. Shouldn't 8i) be a59\frac{a-5}{9}?



I think you're correct, this was my workings.

log3(3b+1)log3(a2)=1log_3(3b+1)-log_3(a-2)=-1

log3(3b+1)+1=log3(a2)log_3(3b+1)+1=log_3(a-2)

log3(3b+1)+log33=log3(a2)log_3(3b+1)+log_33=log_3(a-2)

log33(3b+1)=log3(a2)log_33(3b+1)=log_3(a-2)

3(3b+1)=a23(3b+1)=a-2

9b+3=a29b+3=a-2

9b=a59b=a-5

b=a59b=\frac{a-5}{9}
(edited 7 years ago)
Original post by bulletman54
If you got 16.6 then i think you may only lose 1 mark then just for not subbing for the minimum value


Cool, thanks so much!
Original post by UKoE Luna
I think you're correct, this was my workings.

log3(3b+1)log3(a2)=1log_3(3b+1)-log_3(a-2)=-1

log3(3b+1)+1=log3(a2)log_3(3b+1)+1=log_3(a-2)

log3(3b+1)+log33=log3(a2)log_3(3b+1)+log_33=log_3(a-2)

log33(3b+1)=log3(a2)log_33(3b+1)=log_3(a-2)

3(3b+1)=a23(3b+1)=a-2

9b+3=a29b+3=a-2

9b=a59b=a-5

b=a59b=\frac{a-5}{9}


At this point I give up, Yes you are right however the question in the exam may have been log3(3b+1)log3(2a2)=1\log_3 (3b+1)-\log_3 (2a-2)=-1. It has been too long, I forget. I'll wait till I can see the paper again tomorow
Original post by X_IDE_sidf
we are on to V4 now http://docdro.id/18BTG2C

Thanks


Shouldn't question 9c) be to prove that

P=1000x+x12(4π+3633)P=\frac{1000}{x}+\frac{x}{12}(4\pi+36-3\sqrt{3})

I forget how to LATEX... Shouldn't the fraction outside the brackets be x12\frac{x}{12}
(edited 7 years ago)
Original post by X_IDE_sidf
At this point I give up, Yes you are right however the question in the exam may have been log3(3b+1)log3(2a2)=1\log_3 (3b+1)-\log_3 (2a-2)=-1. It has been too long, I forget. I'll wait till I can see the paper again tomorow

Fair enough, probably the best shout, you can only get so far with memory, but I must thank you for the awesome mark scheme!
Original post by X_IDE_sidf
At this point I give up, Yes you are right however the question in the exam may have been log3(3b+1)log3(2a2)=1\log_3 (3b+1)-\log_3 (2a-2)=-1. It has been too long, I forget. I'll wait till I can see the paper again tomorow


Please quote me in if you give any corrections to the questions.
how many marks would b 90 UMS
for question 6 b, are we supposed tto give answrs to 1 decimal place?
Original post by tory88
Shouldn't question 9c) be to prove that

P=1000x+x12(4π+3633)P=\frac{1000}{x}+\frac{x}{12}(4\pi+36-3\sqrt{3})

I forget how to LATEX... Shouldn't the fraction outside the brackets be x12\frac{x}{12}


yes, you're right
Original post by dadawdawd
for question 6 b, are we supposed tto give answrs to 1 decimal place?


Pretty sure it said to give answers to 1dp yes.
Original post by X_IDE_sidf
The question didn't have limits at that point, part (a) was simply (3xx32)dx\int (3x-x^{\frac{3}{2}})dx


Well then it's just +c
Can somebody type out the actual question 7b? I cant remember what it was and may help me to remember if i got 24.3
Original post by X_IDE_sidf
un=arn1u_n=ar^{n-1}
u9u10=(64)(34)91(64)(34)101=1.602\therefore |u_9-u_{10}| = |(64)(\frac{3}{4})^{9-1}-(64)(\frac{3}{4})^{10-1}| = 1.602 (3 d.p.)


Hey guys I did exactly this in my exam, I remember writing it identically however I got the wrong answer (calculator error maybe?) Would I get the method marks but not the answer mark?
Original post by Dieselblue
Hey guys I did exactly this in my exam, I remember writing it identically however I got the wrong answer (calculator error maybe?) Would I get the method marks but not the answer mark?


I did u10 - u9 or is that wrong? You should get the method mark if it was only a calculating error.
Original post by Brydon hurst
I did u10 - u9 or is that wrong? You should get the method mark if it was only a calculating error.


I did ar^(9-1)-ar^(10-1) I got -0.025 though
Original post by Dieselblue
I did ar^(9-1)-ar^(10-1) I got -0.025 though


Yeah you will definitely get method marks.
Original post by Brydon hurst
Yeah you will definitely get method marks.


Ok thanks thats good to know
Reply 139
any ideas for grade boundaries? roughly how many marks for an a?

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