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C3 June 2016 Model Answers

Wasn't too bad
Most questions were standard.
Lots would have done 6(a) the long tedious way, made algebraic errors and wasted time
9(b)(c) would probably have confused students under exam conditions.

Much easier than last year's paper.
I reckon 62ish for an A

https://drive.google.com/open?id=0B3xSC6XqSy7kQXlSaVdmRk1Ddm8

EDIT; Check my other thread for the C4 solutions

(edited 7 years ago)

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fake arsey

Original post by kprime2

Wasn't too bad

I genuinely love you for doing this.
What are your predictions for an A*/A?

Reply 3

kprime2

Original post by I feel myself

fake arsey

your mum

Reply 4

username2485535

Original post by kprime2

Wasn't too bad
Most questions were standard.
Lots would have done 6(a) the incredibly long and tedious way.
9(b)(c) would probably have confused students.

I reckon 62ish for an A

missing a Q

Reply 5

kprime2

Original post by sayshay

I genuinely love you for doing this.
What are your predictions for an A*/A?

62ish for an A

Reply 6

I feel myself

yeah i agree with kprime, grade boundaries should be
63/64 for an A
67/68 for an A*

Reply 7

ODES_PDES

Original post by I feel myself

fake arsey

Ungrateful!

Reply 8

ODES_PDES

Original post by kprime2

your mum

Childish too!

Reply 9

the_chosen_one97

Original post by kprime2

Wasn't too bad
Most questions were standard.
Lots would have done 6(a) the incredibly long and tedious way.
9(b)(c) would probably have confused students.

I reckon 62ish for an A

Thanks for this kprime!
Just a quick question - wasn't there another question on this paper with a proof and solving an equation in an interval? I don't think I can find it in this pdf. Sorry to bother you

Missing question 8?

Original post by mehtj006

missing a Q

Original post by the_chosen_one97

Thanks for this kprime!

Just a quick question - wasn't there another question on this paper with a proof and solving an equation in an interval? I don't think I can find it in this pdf. Sorry to bother you

Original post by veldt127

Missing question 8?

thanks for letting me know.

I have updated the first post. Click the googledocs link

(edited 7 years ago)

Reply 12

Craig1998

On 6a, I substituted numbers that were outside x>2, would I still be allocated the marks as my A and B were correct.

Reply 13

kprime2

Original post by Craig1998

On 6a, I substituted numbers that were outside x>2, would I still be allocated the marks as my A and B were correct.

Yes. Any two numbers > 2 to form a set of simultaneous equations would have lead to the correct answer

Reply 14

kprime2

Original post by ODES_PDES

Childish too!

it's just banter mate

Reply 15

edothero

I did question 9 a different way, and I suspect so have others;

x=De^{-0.2t}

5 hours after first dose:

x = 15^{-0.2 \times 5}\ \ \rightarrow \ \ x = 5.518191618..

2 hours after second dose:

x = (5.51819... + 15) e^{-0.2 \times 2}

x = 13.753755...

Same goes for part C

(edited 7 years ago)

Reply 16

iBall

Original post by kprime2

it's just banter mate

Thanks for the clear solutions bud, if I have 69/75 in this what would the UMS roughly translate to? Need an A* overall

edit: seen your gb predictions, probably 92ish right?

(edited 7 years ago)

Reply 17

kprime2

Original post by edothero

I did question 9 a different way, and I suspect so have others;

x=De^{-0.2t}

5 hours after first dose:

x = 15^{-0.2 \times 5}\ \ \rightarrow \ \ x = 5.518191618..

2 hours after second dose:

x = (5.51819... + 15) e^{-0.2 \times 2}

x = 13.753755...

seems fine, you get the correct answer

Reply 18

kprime2

Original post by iBall

Thanks for the clear solutions bud, if I have 69/75 in this what would the UMS roughly translate to? Need an A* overall

92ish I reckon

Reply 19

Craig1998

Original post by kprime2

Yes. Any two numbers > 2 to form a set of simultaneous equations would have lead to the correct answer

I used x=0 and x=1 and they both lead to a=3 and b=4..

I really cant afford to lose any more marks, just realised I lost some on the differentiation for forgetting d/dx (cosx) = -sinx.