C1, OCR MEI - 16/05/12 (Answers)

Question 6ii) the binomial expansion, wasn't it (5-2x)^5, therefore meaning that the x^3 coefficient was 10(-2x)^3 * (5)^2 which = -2000 not -720?

Sorry for correcting you, and I'm not saying I'm right! but can someone check this?

The question was (3-2x)^5
so 10(3)^2(-2x)^3 = -720

Oh damn, must have read it wrong :/ Thanks anyway!

If you just put the wrong numbers in you may have got ECF?
I don't know if you can get that on section 1 questions though!

for question 5ii) i compeletly messed up the question in the answer box but did it again on a sheet of paper and got 8/11, I didnt however cross out the answer i put in the box, would i still get the marks?
also on one of the question, where the graph crosses the x-axis, i just put, -18, will this get me the mark?

Hey, this is what i got for C1 MEI today.

any discussion/corrections are welcome!

1. y=-2x+7 and (0,7) and (7/2,0)

2. = SQRT(3a/2c)

3. i) 25
ii) 4/9

4. (x-3)/(x+2)

5. i) 30
ii) 8/11

6. i) 10
ii) -720 (x^3)

7. -SQRT(5) < K < SQRT(5)

8. b= -4 c= -8

9. 6n+9 Show that it is always odd and n must be a multiple of 3 for (6n+9)/9

10.i) SQRT(20) = SQRT(20) QED
ii)1/3 * -3 = -1 QED
iii) Midpoint AC: (2,2) Found they intersect at (2,2) and not (5,3)

11.i) 2x^3 - 5x^2 - 23x - 10
ii) Cubic graph drawn correct way up passing through -2, -0.5 and 5
iii) (0,-18)
iv) (0,-40)

12.i) (4,1) (2.6,-2.6) (0.4,-0.4) give or take 0.1 ish
ii)Showed
iii) x= (3+SQRT(5))/2 and (3-SQRT(5))/2

Don't suppose you could do the same for C2 tomorrow? ;D

No, sorry i am not doing C2 tomorow, but im sure some one will do it

Hey, this is what i got for C1 MEI today.

any discussion/corrections are welcome!

1. y=-2x+7 and (0,7) and (7/2,0)

2. = SQRT(3a/2c)

3. i) 25
ii) 4/9

4. (x-3)/(x+2)

5. i) 30
ii) 8/11

6. i) 10
ii) -720 (x^3)

7. -SQRT(5) < K < SQRT(5)

8. b= -4 c= -8

9. 6n+9 Show that it is always odd and n must be a multiple of 3 for (6n+9)/9

10.i) SQRT(20) = SQRT(20) QED
ii)1/3 * -3 = -1 QED
iii) Midpoint AC: (2,2) Found they intersect at (2,2) and not (5,3)

11.i) 2x^3 - 5x^2 - 23x - 10
ii) Cubic graph drawn correct way up passing through -2, -0.5 and 5
iii) (0,-18)
iv) (0,-40)

12.i) (4,1) (2.6,-2.6) (0.4,-0.4) give or take 0.1 ish
ii)Showed
iii) x= (3+SQRT(5))/2 and (3-SQRT(5))/2