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Mr M's OCR (not OCR MEI) Core 2 Answers May 2012 <strong><font

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for questio 7 if you got the right answer but didnt use the method which will probably be on the markscheme ( the traingle one) would you still get the marks? i ended up using sin^2 +cos ^2 =1 and then devided by cos^2 and did a whole bunch of other stuff :/

Reply 141

Andy16

What was question 7 about? and did it require your calculator to be in degrees mode?

Reply 142

samjj8

Mr M, on question 7ai) I left it as 5/root29. Would I loose a mark for not writing it in standard form?

Reply 143

cantthinkofone

Original post by Andy16

What was question 7 about? and did it require your calculator to be in degrees mode?

its was tana =2/5 find sina or could have been cosa i cant remember exactly

Reply 144

ninuzu

For question 7 I put the answer in decimal form, correct to three significant figures. Would that mean that I get no marks?

Reply 145

Mangodepo11

Original post by Mr M

periodic/repeating is fine

What about reoccuring sequence of o.5 and 4, thats what I put would I get "reoccuring"

also for 0.5<x<2 would I have got any marks for x>2 because i calculated that it needed 2 correctly but did put it the right way around

(edited 11 years ago)

Reply 146

joemkcarr

What was the technique for doing question 7 part A?

Reply 147

Alex Newton

If for question 1)ii) i got the sign between the two expansions wrong so i got all the wrong terms, will i lose both marks or only one??

Reply 148

8xNinjax8

Original post by Mr M

Mr M's OCR (not OCR MEI) Core 2 Answers May 2012

1. (i)

243+810x+1080x^2+720x^3+240x^4+32x^5

(4 marks)

(ii)

486+2160x^2+480x^4

(2 marks)

2. (i)

\frac{x^3}{3}-x^2+5x+k

(3 marks)

(ii)

y=\frac{x^3}{3}-x^2+5x-4

(3 marks)

3. (i)

\frac{2\pi}{5}

(1 mark)

(ii) r = 15 (2 marks)

(iii) 34.4 (3 marks)

4. x = 48.6, 131, 90 degs (6 marks)

5. (a) (i)

u_2 =\frac{1}{2}

and

u_3 = 4

(2 marks)

(ii) Cycles periodically between 4 and 1/2 (1 mark)

(b) a = -2 and d = 2.5 (5 marks)

6. (i) Show trapezium rule (3 mark)

(ii) Sketch graph showing trapeziums under the curve (2 marks)

(iii)

\frac{208}{3}

(4 marks)

7. (a) (i)

\frac{5 \sqrt{29}}{29}

(2 marks)

(ii)

\frac{-2\sqrt{10}}{7}

(3 marks)

(b)

\frac{3\sqrt{3}}{8}

(3 marks)

8. (i) Show a = -4 and obtain b = 3 (6 marks)

(ii)

f(x)=(x-1)(x-2)(x+3)

g(x) also has (x+3) as a common factor (5 marks)

9. (a) (i) Show fourth term (3 marks)

(ii)

x=\frac{4}{3}

(2 marks)

(b) (i)

\frac{1}{2}<y<2

(2 marks)

(ii)

y=\frac{2}{3}

(5 marks)

Hi Mr M,

For the question that asked us to find the values of y for which the GP was valid, I put the modulus of y is less than something...I can't remember exactly what the number was but is there a correct version of the answer involving a modulus sign?

Thanks!

Reply 149

cantthinkofone

Original post by joemkcarr

What was the technique for doing question 7 part A?

i think you had to realise that bcause tana =sina/cos a then if you drew out a trinagle the bottom length would be 5 the other would be 2 and so the hypotenuse would be squareroot 29 ( pythagoras) so then sin would be the bottom legth 5 over the hypotenuse so the answer is 5/square root 29
then u can rationalise the denominator but i dont think you had to :/

im really annoyed i didnt spot that in the exam :/

Reply 150

britash

How did you do questions 7 and 9.
I have *compleltely* different versions.. and i've super messed this up :/

Reply 151

Chocoholic1994Asks

Original post by Mr M

Mr M's OCR (not OCR MEI) Core 2 Answers May 2012

7. (a) (i)

\frac{5 \sqrt{29}}{29}

(2 marks)

(ii)

\frac{-2\sqrt{10}}{7}

(3 marks)

Hi Mr M

Thank again for the mark scheme!
I got
7ai) 5 divided by root 29
ii) 2 root 10 divided by 7 (no minus)

So so you know if these will be marked correct?

Thanks again :smile:

Reply 152

777edr777

Original post by Mr M

Mr M's OCR (not OCR MEI) Core 2 Answers May 2012

6.(iii)

\frac{208}{3}

(4 marks)

Mr M
did qu 6iii) have to be an exact value? I wrote

\frac{208}{3}

BUT then wrote the decimal version next to it and underlined it :frown:

do you think I'd get the mark??

Reply 153

britash

Original post by 777edr777

Mr M did qu 6iii) have to be an exact value? I wrote 208/3 BUT then wrote the decimal version next to it and underlined it :frown:

do you think I'd get the mark??

Same. I got the decimal version. Doubt it matters x

Reply 154

Alex Newton

[QUOTE="Chocoholic1994Asks;37616348"]

Original post by Mr M

Mr M's OCR (not OCR MEI) Core 2 Answers May 2012

7. (a) (i)

\frac{5 \sqrt{29}}{29}

(2 marks)

(ii)

\frac{-2\sqrt{10}}{7}

(3 marks)

Hi Mr M

Thank again for the mark scheme!
I got
7ai) 5 divided by root 29
ii) 2 root 10 divided by 7 (no minus)

So so you know if these will be marked correct?

Thanks again :smile:

About 7ii)
after the exam someone told me you need to make it minus because it wanted to obtuse angle.

I got what you got but then went and did 1-my answer to try and get the obtuse angle :/ :frown:

Reply 155

moose5515

Grade boundaries?? Anyone

Reply 156

h2shin

For the ratio one, will 0<y<2 get 1 mark?

also what do you think the marks for 100ums would be?

Reply 157

max25

Original post by Mr M

Mr M's OCR (not OCR MEI) Core 2 Answers May 2012

1. (i)

243+810x+1080x^2+720x^3+240x^4+32x^5

(4 marks)

(ii)

486+2160x^2+480x^4

(2 marks)

2. (i)

\frac{x^3}{3}-x^2+5x+k

(3 marks)

(ii)

y=\frac{x^3}{3}-x^2+5x-4

(3 marks)

3. (i)

\frac{2\pi}{5}

(1 mark)

(ii) r = 15 (2 marks)

(iii) 34.4 (3 marks)

4. x = 48.6, 131, 90 degs (6 marks)

5. (a) (i)

u_2 =\frac{1}{2}

and

u_3 = 4

\frac{208}{3}

(4 marks)

7. (a) (i)

\frac{5 \sqrt{29}}{29}

(2 marks)

(ii)

\frac{-2\sqrt{10}}{7}

(3 marks)

(b)

\frac{3\sqrt{3}}{8}

(3 marks)

8. (i) Show a = -4 and obtain b = 3 (6 marks)

(ii)

f(x)=(x-1)(x-2)(x+3)

g(x) also has (x+3) as a common factor (5 marks)

9. (a) (i) Show fourth term (3 marks)

(ii)

x=\frac{4}{3}

(2 marks)

(b) (i)

\frac{1}{2}<y<2

(2 marks)

(ii)

y=\frac{2}{3}

(5 marks)

MR M PLEASE HELP. for question three i STUPIDLY did not read the pie after 45, but all the rest of my working was correct. So how many marks will i lose for question three? Also for question 7 I left my answers unsimplified but they were correct, so do i loose marks? THANKS

Reply 158

Dopey'

Thought i done well but lookin at the answers got a c/b lol :frown:

Reply 159

Fresh_Prince_TS

Original post by max25

damn i did the exact same.
For q3 i didn't read the pi part which means i got 3ii wrong too.
q7 also, I did all of my answers in decimal form instead of surd form.
I think mr m has stopped responding, so i guess we'll all have to wait till august