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# OCR C1 Mark Scheme 16/05/12 (NOT MEI) Watch

1. (Original post by As_Dust_Dances_)
The total perimeter was 10y+3 and it had to be between 20 and 54 right?
so 20<10y+3<54
17<10y<51
1.7<y<5.1
no it was 10y +6 the perimeter!
2. (Original post by As_Dust_Dances_)
The total perimeter was 10y+3 and it had to be between 20 and 54 right?
so 20<10y+3<54
17<10y<51
1.7<y<5.1
total perimeter was 10Y+6
3. (Original post by As_Dust_Dances_)
The total perimeter was 10y+3 and it had to be between 20 and 54 right?
so 20<10y+3<54
17<10y<51
1.7<y<5.1
total perimeter was 10y+6
4. (Original post by As_Dust_Dances_)
The total perimeter was 10y+3 and it had to be between 20 and 54 right?
so 20<10y+3<54
17<10y<51
1.7<y<5.1
10y +6

check out http://www.thestudentroom.co.uk/show....php?t=2002389

unofficial mark scheme
5. i got -7<x<4 and 1.7<x<5.1 ...
6. (Original post by I_am_god_123)
total perimeter was 10Y+6
20< 10y + 6 >54!!!!!!!!!!!!!!!!!!!!!!!!!!! !!
7. (Original post by max25)
how did you find the last question?
it was ok, pretty sure i got it right

check out

http://www.thestudentroom.co.uk/show....php?t=2002389
8. (Original post by As_Dust_Dances_)
For the perimeter question I got 17/10<x<51/10
I thought it was in terms of y?

I think I got something like this...

34 <= 10y + 6 <= 54

When simplified gets:

28 <= 10y <= 48

then:

14/5 <= y <= 24/5
9. (Original post by I_am_god_123)
total perimeter was 10Y+6
eeek apologies, wrong question hehe!were both right
10. (Original post by I_am_god_123)
nah it was -7<x<4
but then x must be +ve
for part i) (x+3)(4x)<112 right?

so 4x^2 +12x-112<0

x^2+3x-28

(x+7)(x-4)

You're talking about part 1 right, I was on about part 2..

So yeah it is x<-7 and x>4
11. (Original post by As_Dust_Dances_)
for part i) (x+3)(4x)<112 right?

so 4x^2 +12x-112<0

x^2+3x-28

(x+7)(x-4)

You're talking about part 1 right, I was on about part 2..

So yeah it is x<-7 and x>4
But x cannot be negative - you cannot have a negative length as one of the sides was 4x negative dimensions are impossible so it had to be 0>x>4
12. 100 ****ing percentaaah!
13. (Original post by Ilyas)
100 ****ing percentaaah!
check this out...
http://www.thestudentroom.co.uk/show...389&p=37573386
14. (Original post by max25)
20< 10y + 6 >54!!!!!!!!!!!!!!!!!!!!!!!!!!! !!
yaeh that's correct
15. Question 6

Equation of normal is

4x - 6y -29 = 0
16. would i lose a mark for having it as -4x + 6y + 29?
17. (Original post by As_Dust_Dances_)
for part i) (x+3)(4x)<112 right?

so 4x^2 +12x-112<0

x^2+3x-28

(x+7)(x-4)

You're talking about part 1 right, I was on about part 2..

So yeah it is x<-7 and x>4
this is right.
18. (Original post by PhysicsMan)
Question 6

Equation of normal is

4x - 6y -29 = 0
This rings a bell has the gradient was like 2/3 or something?
19. (Original post by As_Dust_Dances_)
This rings a bell has the gradient was like 2/3 or something?
Yep, the gradient of tangent was -3/2 therefore the gradient of normal is 2/3.
20. (Original post by max25)
20< 10y + 6 >54!!!!!!!!!!!!!!!!!!!!!!!!!!! !!
That can't be correct (I didnt sit the paper though).. You are saying 20 < value > 54... so 20 is bigger than 54? 20 >54: you needed two statements.

Updated: May 16, 2012
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