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OCR C2 4712 14 Jan 2011 Discussion

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Reply 20

Nash24

For the last question I got 40.8 ..
And for the obtuse angle I got 2.45 I think

Reply 21

shufty93

Yeah I got 32 for the area.. There goes one or two marks..

Then the radians one I got 2.45 (3sf) It was like 2.447..... radians
and used that along the rest of the question to get something like an Area of 21.7... THey're usually nice on using rounded values....I think

Reply 22

Mr M

Study Forum Helper

Hi folks - I don't have a C2 paper - our exams officer shot off early at the end of the day before I caught up with him. If someone has one, can they let me know and I will sort out the answers for you. Otherwise it will have to be Monday.

Reply 23

rogersnm

(9iii?) The total area between

f(x)=(x-3)(x+1)(-4x+1)

and the curve is:

36.3945

(Area above the x-axis, from

Unparseable latex formula:

\frac{1}{4}$ to $3

)

+

4.39453

(Area below the x-axis, from

Unparseable latex formula:

-1$ to $\frac{1}{4}

Unparseable latex formula:

= 40.78903$ $(40.8)

Different question: (8i?) The angle of the sector was:

Area of triangle =

\frac{1}{2} \times a \times b \times \sin C = 8

\frac{1}{2} \times 5 \times 5 \times \sin C = 8

25 \times \sin C = 16

\sin C = \frac{16}{25}

Unparseable latex formula:

C = \pi - \arcsin \frac{16}{25} = 2.4470943879632372506$ $(2.45)$ radians$

(Take it away from pi because it's obtuse)

(edited 13 years ago)

Reply 24

oliverpink

i got 40.8 for the last questionbut left it as a fraction, will i still get full marks if that is the correct answer????

Reply 25

DonFahad

Oliverpink, you probably will.

I think it was fairly easy tbh.

Reply 26

oliverpink

how is every1 gettin 2.45 for the angle of that triangle.
i did 0.5x5x5sinc= 8 sinc= 8/12.5

Reply 27

rogersnm

\sin C = \frac{8}{12.5}

is the same as

\sin C = \frac{16}{25}

You then need to do:

Unparseable latex formula:

C = \pi - \arcsin \frac{8}{12.5} = 2.4470943879632372506$ $(2.45)$ radians$

to get the angle in radians

Reply 28

oliverpink

how many marks will i get as i didnt do pie - sin 2/3??

Reply 29

momories

i got 40.8 as well for the last question!

and 2.45 for the radiaan question as well! woo! :biggrin:

Reply 30

rogersnm

Original post by oliverpink

how many marks will i get as i didnt do pie - sin 2/3??

Depends on the mark scheme.. 1 or 2?

(edited 13 years ago)

Reply 31

nomzie

i cant remember what numba this question was but basically does anyone remember the arithmetic questiion with 200 sigma and n=101....how did you do that and what answer did you guys get??

Reply 32

nomzie

what grade boundery do you guys think this paper will have??....considering how hard/easy it was??

Reply 33

rogersnm

Original post by nomzie

i cant remember what numba this question was but basically does anyone remember the arithmetic questiion with 200 sigma and n=101....how did you do that and what answer did you guys get??

It's the sum of the first 200 terms minus the sum of the first 100 terms (the sum of the 101st term to the 200th term)

S_n = \frac{n}{2} \times [2a + (n-1)d]

Unparseable latex formula:

a=5$ and $d=3

So:

Unparseable latex formula:

S_2_0_0 = 100 \times [10 + (199 \times 3)] = 60700

and

Unparseable latex formula:

S_1_0_0 = 50 \times [10 + (99 \times 3)] = 15350

Unparseable latex formula:

S_2_0_0 - S_1_0_0 = 45350

Reply 34

CJAW

I reckon a fairly high grade boundary, probably around 59-61/72. One of the easier C2 papers compared to the rest.

Reply 35

googoo09

can any1 remember the questions so we can send them to MR M and get the proper answers????????

Reply 36

nomzie

Original post by rogersnm

It's the sum of the first 200 terms minus the sum of the first 100 terms (the sum of the 101st term to the 200th term)

S_n = \frac{n}{2} \times [2a + (n-1)d]

Unparseable latex formula:

a=5$ and $d=3

So:

Unparseable latex formula:

S_2_0_0 = 100 \times [10 + (199 \times 3)] = 60700

and

Unparseable latex formula:

S_1_0_0 = 50 \times [10 + (99 \times 3)] = 15350

Unparseable latex formula:

S_2_0_0 - S_1_0_0 = 45350

thank youuuu: :smile:

///do you remmember how many marks that was...
and yes i got it wrong...reaally wrong!

Reply 37

nomzie

sorry keep asking questions but what about the one where you had to intergrate something divided by x
what was the answer to that folks???

Reply 38

rogersnm

Original post by nomzie

thank youuuu: :smile:

///do you remmember how many marks that was...
and yes i got it wrong...reaally wrong!

Probably ~4 marks

Original post by nomzie

sorry keep asking questions but what about the one where you had to intergrate something divided by x
what was the answer to that folks???

If I recall correctly it was something like:

Unparseable latex formula:

\frac{x^3 + 3x^1^/^2}{x}

which is the same as

Unparseable latex formula:

x^2 + 3x^-^1^/^2

which you can then integrate.

(edited 13 years ago)

Reply 39

Mr M

Study Forum Helper

Noone have a paper to send me to do then? I have just posted the Core 4 answers if anyone is interested.

http://www.thestudentroom.co.uk/showthread.php?p=29375064#post29375064