OCR (Not MEI) C2 May 2013 (17.5.13) UO Markscheme

8 'show that' question:
y=y
a^x=4b^x
log2(a^x)=log2(4)+log2(b^x)
x(log2(a)-log2(b)=2
ab=2 therefore b=2/a, sub this in to get
x(log2(a)-log2(2/a))=2
x(log2(a)-(log2(2)-log2(a))=2
x(log2(a)-1+log2(a))=2
x(2log2(a)-a)=2
Therefore x= 2/(2log2(a)-1)
Hope this helps! (:

Thank you! I didn't get it right but hopefully I will get something for trying! I ended up with x(2log2a-1)=2x then I just wrote the equation

Reply 21

Whyllee

Is it possible for someone to put up the marks next to the answers, so I can see how many I lost?

Reply 22

sugartown

Can someone explain why the first one was 6.3 and not 9.56 or something? I got 6.3 before I x the bracket and then 6.3 x 3/2? So confused and feel a bit stupid considering it was such easy marks

Reply 23

Good@Math

Original post by thebigman1

Can you put the marks for the question by the question please?

Done

Reply 24

CDL

was question 5) the triangle/sector question? for ii) i got 34 but for 5i) i seem to remember my answer being 102 for the area?? am i wrong?

Reply 25

purplemind

6

Original post by Majeue

By the way for question 5ii, the answer is 36 not 34. It was 12.8+12.2+11=36

But 16-7=9 not 11

Reply 26

Majeue

1

Original post by purplemind

But 16-7=9 not 11

my bad, thought it was 11 for some reason, I did actually get 34 lol.

Reply 27

chuckynoriss

Original post by Whyllee

Anyone hazard a guess at the grade boundaries? (it was relatively easy)

Using the grade boundaries for June 2012 (which was also a relatively easy paper) 57 maybe for an A. (it's usually in the 50's to get an A)

Reply 28

chuckynoriss

7ii) how is it 37/30 because you do the integration of curve- tangent from 1 to 4 and 3/2( 1.5) is bigger than 1 so lower limit is 1

Reply 29

CDL

was question 5) the triangle/sector question? for ii) i got 34 but for 5i) i seem to remember my answer being 102 for the area?? am i wrong?

Reply 30

Music99

4

Original post by CDL

was question 5) the triangle/sector question? for ii) i got 34 but for 5i) i seem to remember my answer being 102 for the area?? am i wrong?

that was the big sector. You wanted the smaller one.

Reply 31

CDL

Original post by Music99

that was the big sector. You wanted the smaller one.

okay so will that be 3 marks out of 4??

Reply 32

DingDong!

7

Did any one else find the equation of the tangent and theb integrate between the two points and take it away from the integral of the curve?? Loads of people seem to have used a triangle :s

Posted from TSR Mobile

Reply 33

chuckynoriss

Original post by chuckynoriss

7ii) how is it 37/30 because you do the integration of curve- tangent from 1 to 4 and 3/2( 1.5) is bigger than 1 so lower limit is 1

someone help me out how did they do it

Reply 34

roar96

8

Original post by DingDong!

Did any one else find the equation of the tangent and theb integrate between the two points and take it away from the integral of the curve?? Loads of people seem to have used a triangle :s

Posted from TSR Mobile

I worked out the area under the curve and then took away the area under the line too... I can't see how it would get the wrong answer and I assumed that was what they wanted given they got you to integrate the curve for the question before... so hopefully there's multiple methods...

Reply 35

Majeue

1

Original post by DingDong!

Did any one else find the equation of the tangent and theb integrate between the two points and take it away from the integral of the curve?? Loads of people seem to have used a triangle :s

Posted from TSR Mobile

Yes I did it that way.. Does anyone remember what question 9i was?

Reply 36

sugartown

PLEASE Can someone explain why the first one was 6.3 and not 9.56 or something? I got 6.3 before I x the bracket and then 6.3 x 3/2? So confused and feel a bit stupid considering it was such easy marks

Reply 37

chuckynoriss

Original post by Majeue

Yes I did it that way.. Does anyone remember what question 9i was?

that was finding the remainder when you substitute i think it -1/2 as x into the equation

Reply 38

chuckynoriss

Original post by sugartown

PLEASE Can someone explain why the first one was 6.3 and not 9.56 or something? I got 6.3 before I x the bracket and then 6.3 x 3/2? So confused and feel a bit stupid considering it was such easy marks

you had to start from x=5 and 3 trips keeping adding 2 until you got x=11
so x values were x=5 x=7 x=9 x=11

Reply 39

tgtips372

Hey

the reason you don't multiply the 6.3 by 3/2 is because the trapezium starts with h/2, there were 3 strips but the width of each strip was 2, so the h/2 was equal to 2/2 so basically it stays as 6.3. Hope that helps! :smile:

OCR (Not MEI) C2 May 2013 (17.5.13) UO Markscheme

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you