C1 Maths AS aqa 2016 (unofficial mark scheme new)

K was 65. To find the radius you used the length equation so: r^2 = 7^2 + 4^2 = 65 hence r = root 65. K is r^2 therefore K was 65.

Reply 101

ExamsCauseStress

1

Original post by Zaydy33

Hi everyone, I'm pretty sure I've got almost everything correct but for the length of CT, I stupidly left it as root 81 instead of 9. Do you think they may allow it in the mark scheme as normally it says OE (or equivalent) and root 81 is equivalent to 9!

Thanks

Difficult to say, at most you've lost 1 mark and 74/75 will still get you 100 UMS so you shouldn't worry

Reply 102

Ywna097

1

Does anyone remember the formula we had to intergrate?

(edited 7 years ago)

Reply 103

chloelaura27

6

For q7bi and bii, if I got the right answer but forgot to simplify the fraction how many marks will I lose?

Reply 104

df97

1

For question 4d shouldn't it be -14? (-2 * -14=28 +20=48)

Reply 105

ExamsCauseStress

1

Original post by chloelaura27

For q7bi and bii, if I got the right answer but forgot to simplify the fraction how many marks will I lose?

1 at most.

Reply 106

BlackthornRose

2

Original post by Jacobisswaggy

For the one where you had to prove it was a minimum value, I believe you first need to find that it is a stationary point by subbing in to dy/dx, then subbing in to d^2y/dx^2 to show it is a minimum.

I base this on the fact the question was 4 marks, and it wouldn't be 4 marks for only subbing in to d^2y/dx^2.

I did the same but can't remember what value i actually got when i put it into the second derivative equation, and am now wondering if i differentiated it correctly. Do you remember what the formula was for d^2y/dx^2? And the coordinate that we were supposed to sub in as well? Thanks very much if you can.

I hardly remember question 1 and forgot how to get coordinates of B as i don't remember getting (-3, 4) i I just seriously don't remember question one at all. I'm sure i checked it but if someone can tell me how they came to those coordinates?

Reply 107

Ywna097

1

Original post by BlackthornRose

I did the same but can't remember what value i actually got when i put it into the second derivative equation, and am now wondering if i differentiated it correctly. Do you remember what the formula was for d^2y/dx^2? And the coordinate that we were supposed to sub in as well? Thanks very much if you can.

I hardly remember question 1 and forgot how to get coordinates of B as i don't remember getting (-3, 4) i I just seriously don't remember question one at all. I'm sure i checked it but if someone can tell me how they came to those coordinates?

I recall the x-coordinate being -1.5 , it was in mixed fraction form i think.

Reply 108

ssmith04

7

If I got the coordinates wrong for B on 5b) but did 5c) correctly (with the wrong coordinates) will I get follow through marks, if so would it be all 5 or would I have lost some for having the wrong coordinates?

Reply 109

Zaydy33

1

Original post by ExamsCauseStress

Difficult to say, at most you've lost 1 mark and 74/75 will still get you 100 UMS so you shouldn't worry

Okay thank you! I hope i get 100 UMS cos core 2 is gonna be hard!

Reply 110

Parhomus

8

I think that getting m wrong for 1a wouldn't matter because 1b was simultaneous equations and 1c was just subbing in the coordinates into one of the equations (can't remember which)

Reply 111

BlackthornRose

2

Original post by Ywna097

I recall the x-coordinate being -1.5 , it was in mixed fraction form i think.

Thanks

Reply 112

Pentaquark

13

The equation for the integral was 4 - x^2 - 3x^3 I think as
I remember integrating it to give [4x - x^3/3 - (3x^4)/4] between -2 and 1
Sub in -2 giving -52/3
Sub in 1 giving 35/12

So 35/12 - -52/3 gives 81/4 which is 20.25
Then subtract from the area of the triangle
20.25-9 = 11.25 or 45/4.

Reply 113

Ywna097

1

Original post by Pentaquark

The equation for the integral was 4 - x^2 - 3x^3 I think as
I remember integrating it to give [4x - x^3/3 - (3x^4)/4] between -2 and 1
Sub in -2 giving -52/3
Sub in 1 giving 35/12

So 35/12 - -52/3 gives 81/4 which is 20.25
Then subtract from the area of the triangle
20.25-9 = 11.25 or 45/4.

Thanks

Reply 114

BlackthornRose

2

Original post by Parhomus

I think that getting m wrong for 1a wouldn't matter because 1b was simultaneous equations and 1c was just subbing in the coordinates into one of the equations (can't remember which)

Do you happen to remember the simultaneous equations? I'd hate to lose marks on the first question and it's the one I remember least as I probably gave it the least thought.

Reply 115

username1022139

20

Original post by qwertyuiop1998

Any estimates for 100 UMS?

I'm guessing about 72 for 100 UMS.

60 for an A.

56 for a B.

52 for a C.

Reply 116

Sniperdon227

5

I reckon like 72/75 will be 100UMS

Reply 117

timtjtim

2

Unofficial Mark scheme for C1 AQA 2016

It would help if you could link answers to questions as I can't remember them :smile:

Questions:

1)
a)Asked to work out gradient of a tangent, m=

-{5\over3}

[2]
b)Asked to find co-ordinates of B B(-3,4) [3]
c)Asked to find K K= -30 [2]

2)
a) Simplify (3√5)^2 = 45 [1]
b) 75-32√5

3) a) y=(x-7/2)^2 - 41/4
b) min value = -41/4
c) Translation of (1/2 , 41/4)

4) a) show that (x+3) was a factor of x^3 - 5x^2 -8x + 48, p(-3) = 0, (x+3) is a factor of p(x).
b) three linear factors of p(x) = (x+3)(x-4)(x-4)
c) find remainder when p(x) was divided by (x+2) R=20
d) Factorise p(x) using (x+2) R = (x-2)(x^2-3x+14) + 20 [3]

5) a) asked to find equation of circle (x-5)^2+(y+3)^2=65 (note 65 = r^2) [3]
b) asked to find co-ordinates of B (AB is diameter) B ( 12, -7) [2]
c) asked to find equation of tangent at A 7x-4y+18=0 [5]
d) asked to find length of CT = 9 [2]

6) a) y=-32x-40
b)Q(-5/4) [1]
c) upside down positive graph passing through y axis at 8 [2]
d) x = -1±√5

7) a) I think there were 4 parts to this question I can't remember part a and b
b)
c) Definite integral of

\int_{-2}^{1} 4-x^2-3x^3 = [ {{-3x^4}\over{4}} - {{x^3} \over {3}} + 4x + c]

= 81 /4 [5]
d) Area of shaded region =

{84\over4} - {24\times2-{5\over4}\over2}

= 45/4 [3]

8) a) can't remember anything except the answers were k>6 and k<-3/2

Answers that need a question to be assigned to
- k=4 and k=20
- d^2y/dx^2= - 2x - 9x^2 sub in x-coordinate of p to get 45, 45>0 therefore minimum

Updated again.

Reply 118

qwertyuiop1998

1

If I got the wrong equation when completing the square for 8-4x-2x^2. Could i still get marks for the next part where it asked to calculate the roots by error carried forward

Could i also get error carried forward on question 7 if i got the wrong equation in 7a leading to the wrong co-ordinate for Q and so the wrong area of the triangle