Hi sir, for 3ii, I equted the coeffeicent to k the constant and not the constant term, how many marks would i get if any? My solutions were 0 and 1/9 by the way.
Also for 9ii I got root 3/2 for k which is correct but got a is equal to 10/3?
Finally for 9iii i said that the period of tan was pi/a and also wrote "pi/a -x1=x2" and said xq and xw were the solutions. After that o did tan -1 root3 and got pi/3 and 4pi/3 but did not relate them to ax at all, how many dropped?

Reply 88

Nikita_2313

Original post by Mr M

Mr M's OCR (not OCR MEI) Core 2 Answers May 2016

1. (i) 10 cm (2 marks)

(ii) 5.04 cm (2 marks)

2. (i)

\displaystyle \frac{3 \pi}{10}

(2 marks)

(ii)

r=20.4

(3 marks)

3. (i)

\displaystyle 27 +27kx+9k^2x^2 +k^3x^3

(4 marks)

(ii)

k=\pm \sqrt{3}

(2 marks)

4. (i)

\displaystyle \log_3 \frac{x^2}{x+4}

(2 marks)

(ii)

x = 12

(4 marks)

5. (a)

\displaystyle \frac{x^4}{2} -x^3 +2x^2-6x+k

(3 marks)

(b) (i)

\displaystyle \frac{2}{a^2} - \frac{6}{a} + 4

(4 marks)

(ii) 4 (1 mark)

6. (i)

k=91

(3 marks)

(ii)

\displaystyle S_{16} = 978

(2 marks)

(iii)

N=38

(6 marks)

7. (i) Quotient

x^2-4x+3

and remainder 0 (3 marks)

(ii)

x=1

x=-1

x=3

(3 marks)

(iii) Show (2 marks)

(iv)

\displaystyle \frac{512}{15}

(4 marks)

8. (i) Translation by 2 units in the positive x direction (2 marks)

(ii) Stretch parallel to the y axis scale factor

\displaystyle \frac{1}{9}

(2 marks)

(iii) Sketch showing

(0, \frac{1}{9})

as the only point of intersection (2 marks)

(iv)

x=6.73

(3 marks)

(v) 9.60 (3 marks)

9. (i)

\displaystyle \frac{2 \pi}{a}

(1 mark)

(ii)

\displaystyle a=\frac{5}{3}

and

\displaystyle k=\frac{\sqrt{3}}{2}

(3 marks)

(iii)

\displaystyle x=\frac{\pi}{3a}

and

\displaystyle x=\frac{4 \pi}{3a}

(4 marks)

Sorry guys I made a mess of 9(ii) at the start - I didn't notice k had to be positive. It's right now.

If in question 7iv i got the right answer 512/15, but then proceeded to make it into a mixed number, but did it incorrectly, would I lose a mark? I did not cross out 512/15

Reply 89

Mia122333

Original post by Mr M

Mr M's OCR (not OCR MEI) Core 2 Answers May 2016

1. (i) 10 cm (2 marks)

(ii) 5.04 cm (2 marks)

2. (i)

\displaystyle \frac{3 \pi}{10}

(2 marks)

(ii)

r=20.4

(3 marks)

3. (i)

\displaystyle 27 +27kx+9k^2x^2 +k^3x^3

(4 marks)

(ii)

k=\pm \sqrt{3}

(2 marks)

4. (i)

\displaystyle \log_3 \frac{x^2}{x+4}

(2 marks)

(ii)

x = 12

(4 marks)

5. (a)

\displaystyle \frac{x^4}{2} -x^3 +2x^2-6x+k

(3 marks)

(b) (i)

\displaystyle \frac{2}{a^2} - \frac{6}{a} + 4

(4 marks)

(ii) 4 (1 mark)

6. (i)

k=91

(3 marks)

(ii)

\displaystyle S_{16} = 978

(2 marks)

(iii)

N=38

(6 marks)

7. (i) Quotient

x^2-4x+3

and remainder 0 (3 marks)

(ii)

x=1

x=-1

x=3

(3 marks)

(iii) Show (2 marks)

(iv)

\displaystyle \frac{512}{15}

(4 marks)

8. (i) Translation by 2 units in the positive x direction (2 marks)

(ii) Stretch parallel to the y axis scale factor

\displaystyle \frac{1}{9}

(2 marks)

(iii) Sketch showing

(0, \frac{1}{9})

as the only point of intersection (2 marks)

(iv)

x=6.73

(3 marks)

(v) 9.60 (3 marks)

9. (i)

\displaystyle \frac{2 \pi}{a}

(1 mark)

(ii)

\displaystyle a=\frac{5}{3}

and

\displaystyle k=\frac{\sqrt{3}}{2}

(3 marks)

(iii)

\displaystyle x=\frac{\pi}{3a}

and

\displaystyle x=\frac{4 \pi}{3a}

(4 marks)

Sorry guys I made a mess of 9(ii) at the start - I didn't notice k had to be positive. It's right now.

Hi 2ii) I got 21. Something I laid it out correctly ie 2r + r3/5 pi then = but then divided by 3/5pi and got wrong answer?
For 9ii) I got a = 5 how many marks if any do you think I will get?
And 7iv) I integrated between 3 and -1 but didn't get the correct answer think I just put in my calculator wrong but showed my method??
9iii) I got tan ax then substituted my a value from previous question which i didn't read the question?
How many marks do you think I got from them if any? And do you think 60 will b a A?

Thanks

(edited 7 years ago)

Reply 90

Mr M

Study Forum Helper

Original post by Nikita_2313

If in question 7iv i got the right answer 512/15, but then proceeded to make it into a mixed number, but did it incorrectly, would I lose a mark? I did not cross out 512/15

It's fine to have a mixed number. We tend not to ever use them after GCSE.

Reply 91

Nikita_2313

Original post by Mr M

It's fine to have a mixed number. We tend not to ever use them after GCSE.

Yes, but if I converted it INCORRECTLY into a mixed number, would I lose a mark, provided that i did not cross out the correct top-heavy fraction answer?

Reply 92

Mr M

Study Forum Helper

Original post by Mia122333

For 9ii) I got a = 5 how many marks if any do you think I will get?
And 7iv) I integrated between 3 and -1 but didn't get the correct answer think I just put in my calculator wrong but showed my method??

How many marks do you think I got from them if any? And do you think 60 will b a A?

Thanks

9ii) I made that mistake first time! You might get 1 mark.

7iv) Drop 1 or 2.

I don't guess boundaries.

Reply 93

Mtjk

How many marks would you get if you put k=1/9

Reply 94

Psraim

Original post by Mr M

Mr M's OCR (not OCR MEI) Core 2 Answers May 2016

1. (i) 10 cm (2 marks)

(ii) 5.04 cm (2 marks)

2. (i)

\displaystyle \frac{3 \pi}{10}

(2 marks)

(ii)

r=20.4

(3 marks)

3. (i)

\displaystyle 27 +27kx+9k^2x^2 +k^3x^3

(4 marks)

(ii)

k=\pm \sqrt{3}

(2 marks)

4. (i)

\displaystyle \log_3 \frac{x^2}{x+4}

(2 marks)

(ii)

x = 12

(4 marks)

5. (a)

\displaystyle \frac{x^4}{2} -x^3 +2x^2-6x+k

(3 marks)

(b) (i)

\displaystyle \frac{2}{a^2} - \frac{6}{a} + 4

(4 marks)

(ii) 4 (1 mark)

6. (i)

k=91

(3 marks)

(ii)

\displaystyle S_{16} = 978

(2 marks)

(iii)

N=38

(6 marks)

7. (i) Quotient

x^2-4x+3

and remainder 0 (3 marks)

(ii)

x=1

x=-1

x=3

(3 marks)

(iii) Show (2 marks)

(iv)

\displaystyle \frac{512}{15}

(4 marks)

8. (i) Translation by 2 units in the positive x direction (2 marks)

(ii) Stretch parallel to the y axis scale factor

\displaystyle \frac{1}{9}

(2 marks)

(iii) Sketch showing

(0, \frac{1}{9})

as the only point of intersection (2 marks)

(iv)

x=6.73

(3 marks)

(v) 9.60 (3 marks)

9. (i)

\displaystyle \frac{2 \pi}{a}

(1 mark)

(ii)

\displaystyle a=\frac{5}{3}

and

\displaystyle k=\frac{\sqrt{3}}{2}

(3 marks)

(iii)

\displaystyle x=\frac{\pi}{3a}

and

\displaystyle x=\frac{4 \pi}{3a}

(4 marks)

Sorry guys I made a mess of 9(ii) at the start - I didn't notice k had to be positive. It's right now.

For question 7iv, how many marks would I lose for doing (153/5) + (53/5) instead of (153/5) + (53/15) ?
And for question 9iii how many marks would I lose for pia/3 and 4pia/3 instead of pi/3a and 4pi/3a?

(edited 7 years ago)

Reply 95

Mr M

Study Forum Helper

Original post by bluegirl64

Can someone pls go through q 6(iii)?

\displaystyle \sum_{n=1}^{\infty} W_n = 1200

\displaystyle \frac{N}{2}(2a+(N-1)d)>1200

Let a = 5 and d = 1.5 and solve.

Reply 96

Mr M

Study Forum Helper

Original post by Nikita_2313

Yes, but if I converted it INCORRECTLY into a mixed number, would I lose a mark, provided that i did not cross out the correct top-heavy fraction answer?

Your marker will drop the code ISW onto your script to mean ignore subsequent working.

Reply 97

Mr M

Study Forum Helper

Original post by Saching99

if for 3ii , we used 3 from (3+kx) as the constant instead of 27 and got +-1/rt3 do we drop both or jsut one

Drop both.

Reply 98

Csd1999

For the original log question i) I got it down to log3(x^2) -log3(x+4) but I stupidly simplified to log3(x/x+4) so obviously I carried that through to part ii which then gave me a wrong answer.. How many marks would likely I get out of 6?