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AQA C2 Unofficial Mark Scheme 20 May 2015

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Reply 60

Sunshine98

Original post by WillNegForReps

i got q as -64 or something like that. q sounds better at 4.
p was 0.8 or 4/5. i guess most agree on that one.

Yes Q was 4 and P was 0.8

Reply 61

jjsnyder

Original post by Hexaneandheels

Oh crap! You are right. GRRRR. What do you think 67/75 will give approx do you have any idea what 100UMS could be for this?
Also for the last question, do you think I will get a mark for raising all the equation 2 to the power of them all to remove the logs?

My guess is similar grade boundaries to usual - probably around 72/3 for 100UMS

Reply 62

I Persia I

I kept getting -2root2 for the tantheta :frown:

Reply 63

jjsnyder

Original post by Seveers

pretty sure i got: 3c wrong. 5a 6ciii i put overestimate. and i forgot what question 8 was...

how many marks dropped is that?

Integral was an overestimate, but because you took it away from the 27 it resulted in an underestimate.

Reply 64

Seveers

Original post by I Persia I

I kept getting -2root2 for the tantheta :frown:

Same. hoping to only drop 1 mark though....or maybe they wont notice :tongue:

Reply 65

jjsnyder

Original post by I Persia I

I kept getting -2root2 for the tantheta :frown:

Remember that cos(-theta) = cos(theta)

Reply 66

2014_GCSE

Original post by Scott Griffiths

i got 13.7.. it wasnt a right angled triangle as some thought

Yes it was...?

If it goes from the midpoint of BC, then it goes straight up making a right angle.

11.1 too folks.

Reply 67

Hexaneandheels

But people are comparing this to last year paper which has lower boundary for 100UMS. I hope you are wrong because I think many have struggled with a couple of big markers on this

Original post by jjsnyder

My guess is similar grade boundaries to usual - probably around 72/3 for 100UMS

Reply 68

antrum95

Original post by MahirYmaths

I got that too, everyone has conflicting opinions...

You got both of mine? Do you think they were right??

Reply 69

jjsnyder

Original post by antrum95

You got both of mine? Do you think they were right??

I shall write out the solution ( I will try and remember anyway!)

Reply 70

SunDun111

i got 13.6 i found the area of the triangle and divided it by 5.. don't ask why but i might of got 13.7 but rounded it wrong, would i get any marks? I dont know why i did what i did i am just stupid :frown:

yeah

I got 11.6 for AM?

Original post by SunDun111

i'm sure i got 13.5 for that qs :/

Reply 74

antrum95

Original post by jjsnyder

I shall write out the solution ( I will try and remember anyway!)

Yes please!!!

Reply 75

I Persia I

Original post by jjsnyder

Remember that cos(-theta) = cos(theta)

Reckon I'll get 1 mark for that or not?

Original post by 2014_GCSE

Yes it was...?

If it goes from the midpoint of BC, then it goes straight up making a right angle.

11.1 too folks.

?
I found the area of the triangle using 1/2absinC then equalled it to 1/2x20xstraight line then rearranged to find the length of the straight line and got 13. something?

what would 90 ums be

Original post by I Persia I

I found the area of the triangle using 1/2absinC then equalled it to 1/2x20xstraight line then rearranged to find the length of the straight line and got 13. something?

I just used the cosine rule. With 10, 15.6 and cos(48).

Reply 78

ilovecake123

Original post by jjsnyder

Sorry if I missed out some questions, couldn't remember them all! This is for AQA, Mark values are guesses so some may be incorrect
Mark Scheme:
Q1. Angle is 6/5 Radians
Therefore Perimeter is 16cm (4 Marks)
Q2.
a) Use sine rule to show side is 15.6 (3 Marks)
b) AM has length 13.7 (4 Marks)
Q3.
a) u3 = 17.28 (2 Marks)
b) Limit = 120 (2/3 Marks)
c) Sum = 25.92 (3 Marks)
Q4.
a) find second derivative: y= -4x^-3 - 1/4 (3 Marks)
b) x=2 (4 Marks)
c) second derivative < 0 therefore max (?)
d) integrate to get y= equation (4 Marks)
Q5. A) P=0.8 q=4 (5 Marks)
b)195 (2 Marks)
Q6.
a) Translation vector {0,1} (2 Marks)
b) Stretch SF 9 in x-axis (2 Marks)
c) i) 27 (1 Mark)
ii) 19.7 (4 Marks)
iii) 7.3, underestimate (3 Marks)
Q7.
a) -0.056,1.8 (2/3 Marks)
b) cosx=-1/3 and ½ (3 Marks)
c) Show tanx =2root2, there were many methods here (3 Marks)
Q8.
Y=(2/3)x + 3/8 (5 Marks)
Q9.
a)x=0.744 (3 Marks)
b) a=(k/2)^3/2 (3 Marks)
c) n=1.5 or n=-0.25 (5 Marks)

for 3c) how did you do this question/method, i can't remember what i did, but if you did the same method as me we are likely to have got the right answer

Reply 79

jjsnyder

Original post by I Persia I

Reckon I'll get 1 mark for that or not?

?
I found the area of the triangle using 1/2absinC then equalled it to 1/2x20xstraight line then rearranged to find the length of the straight line and got 13. something?