Unofficial mark scheme ocr core 1 16/05/12

UNOFFICIAL MARK SCHEME

1 x3 -6x2 -11
2 2(x-5)2 -1 (or this might have been another question?)
3
4
5 i) graph
ii) a translation of 4 units in the positive x direction
iii) y = square root (1/5 x)
6
7 16+6 root 7, 16- 6 root 7
8 i)stationary point is at (-2, 48)
ii) this is a minimum
iii) x3 + 4 increase as x increases when x>2
9 i) -7 < x < 4
ii) 1.4 < y < 4.8
10 i) centre (5, -2), Diameter = 10
ii) y = 2x -12
iii) length CP = 2 root 5, P is inside the Circle
iv) y=2x doesn't meet the circle

can anyopne help with the rest of the answers and i will update this post

8(i) it was (-2,-48)
9(i) is 0<x<4 (how can you have a -ve length)

8(i) it was (-2,-48)
9(i) is 0<x<4 (how can you have a -ve length)

it can be negative because it gets squared to would go positive anyways

:O didn't think of that, depends whether length is a vector..., because if its in the opposite direction then it could be negative

UNOFFICIAL MARK SCHEME

1 x3 -6x2 -11
2
3
4 i) 2(x-5)2 -1
ii) minimum point = (5, -1)
5 i) graph
ii) a translation of 4 units in the positive x direction
iii) y = square root (1/5 x)
6
7 16+6 root 7, 16- 6 root 7
8 i)stationary point is at (-2, -48)
ii) this is a minimum
iii) x3 + 4 increase as x increases when x>2
9 i) -7 < x < 4
ii) 1.4 < y < 4.8
10 i) centre (5, -2), Diameter = 10
ii) y = 2x -12
iii) length CP = 2 root 5, P is inside the Circle
iv) y=2x doesn't meet the circle

can anyopne help with the rest of the answers and i will update this post

For question 7 i got 16+6root 7 and 2+6root 7? As you 3+or-root 7 from the quadratic right? And I let y=x^1/2 so you had to square each one. You get 9-7 for the second one.

you get (3+ root7)2 and (3- root 7)2

The first gives 9 +6 root 7 +7

the second gives 9-6root 7 +7

because -root 7 * -root 7 = 7 because - x - =+

1 x3 -6x2 -11
2 i) k=1/4
ii) k=-3/2
iii) k= 24
3
4 i) 2(x-5)2 -1
ii) minimum point = (5, -1)
5 i) graph
ii) a translation of 4 units in the positive x direction
iii) y = square root (1/5 x)
6 Normal to the curve = 4x -6y -29 =0
7 16+6 root 7, 16- 6 root 7 (16+- 6 root 7)
8 i)stationary point is at (-2, -48)
ii) this is a minimum
iii) x3 + 4 increase as x increases when x> -2
9 i) 0 < x < 4 (length can't be negative)
ii) 1.4 < y < 4.8
10 i) centre (5, -2), Diameter = 10
ii) y = 2x -12
iii) length CP = root 20, P is inside the Circle
iv) y=2x doesn't meet the circle because b2-4ac<0

2i was 1/5 .. ii was -3/2 and iii was 24 ... Also for 6 i got 4x-6y+13 ?

What was question 6 again?

2)ii was 1/4

it was + 29 not 13