2014 HSC Extension 2 Maths Carrotsticks' Solutions (1 Viewer)

[Carrotsticks]

Here are my HSC Solutions for this year.

Please feel free to hit me up with a message if you see anything that may be incorrect/needs clarifying!

https://www.dropbox.com/s/dthlsed7gfknygt/HSC 2014 Extension 2 Solutions.pdf?dl=0

My comments on this year's paper:

- Not particular interesting or inspiring.

- Some results were mis-leading in the sense that they were not required to be used to solve the problem. Almost as if they wrote the question with a very specific method in mind, without realising that the result they were building towards could have been proven in a few lines.

- No probability or perms & combs? That's new (or at least as far as my memory goes).

- No explicit induction problem? I know that we want to promote some sort of Mathematical creativity, but you can do that without having to leave out something like that.

- Partial fractions twice?

- t formula twice? (for those who didn't realise that you could have just differentiated for the 't formula MC question'.

- Question 9 of MC, why is that in an Extension 2 paper?

- Some of the wording is a bit strange (ie: why did they have to say 'real' in Q12 (b) (ii)?, Q14 (a) (ii), did they mean 'non-real'?).

- Q14 (b) (i) needs absolute values on the sine and cosine functions.

- Q15 (c) (ii), quadratic formula, really? Also, how is this related to the other parts?

- Q16 (c) the reason why I never put such questions in my exams (least of all as the last question), is because there may always be a way to get it out in a few lines, which there was (reverse quotient rule).

 

[dan964]

draw and scan.

 

[IR]

All good bro.

 

[mreditor16]

Hold tight! The graphs are taking longer to draw via computer than expected.

let's see if we can beat your time last year It was 4:08 PM that you uploaded last year

 

[Carrotsticks]

Not going to beat that one because I spent a lot more time on graphs this year to make it look nice.

Also I'm going to be completely honest and I'm currently stuck on the conical pendulum problem part (ii) haha oh dear.

 

[mreditor16]

Not going to beat that one because I spent a lot more time on graphs this year to make it look nice.

Also I'm going to be completely honest and I'm currently stuck on the conical pendulum problem part (ii) haha oh dear.

change cos^2 pi to 1 - sin^2 pi

and then go from there and use quadratic formula

 

[aDimitri]

Not going to beat that one because I spent a lot more time on graphs this year to make it look nice.

Also I'm going to be completely honest and I'm currently stuck on the conical pendulum problem part (ii) haha oh dear.

i have never been this proud before

 

[aDimitri]

change cos^2 pi to 1 - sin^2 pi

and then go from there and use quadratic formula

yup

 

[mreditor16]

i have never been this proud before

ditto

 

[billym]

Not going to beat that one because I spent a lot more time on graphs this year to make it look nice.

Also I'm going to be completely honest and I'm currently stuck on the conical pendulum problem part (ii) haha oh dear.

I just finished writing up my own solutions for that question, mine feels pretty clumsily worded though. Easy enough to see how to get the result, but my wording of the actual proof to justify the inequality is a bit shaky.

 

[mreditor16]

I just finished writing up my own solutions for that question, mine feels pretty clumsily worded though. Easy enough to see how to get the result, but my wording of the actual proof to justify the inequality is a bit shaky.

same same :/

 

[IR]

Same I got stuck. But last minute I thought of using. Not enough time

 

[Carrotsticks]

I just finished writing up my own solutions for that question, mine feels pretty clumsily worded though. Easy enough to see how to get the result, but my wording of the actual proof to justify the inequality is a bit shaky.

My gut instinct told me to do that initially and I rejected immediately because "As if they would make us do that".

Apparently so =/

Also, finally up to Question 16 (b) !

Seems like they finally decided to finish off the proof of the Leibniz series from that 90's HSC paper that they left in the air.

 

[Carrotsticks]

Okay finished, just double checking everything now. I'm in a bit of a panic because I have a class to teach soon!

 

[mreditor16]

Okay finished, just double checking everything now. I'm in a bit of a panic because I have a class to teach soon!

ditch it, legit for the great good, Carret. for the greater good

do you want to cross-check with mine?

okay here are some of my answers. one disclaimer - I did not get time to check answers.

q11 a) I) root 2 cis ( - pi /4) ii) -4 / 5 - 2/5 i

b) pi - 6 all over 2 (pi)^2

e) 216 pi units cubed

Q12. b) ii) pi / 18 , 11pi / 18, 13 pi /18
d) iii) 3 pi - 8 all over 12

Q13 a) 2 (root 3) - 3 all over 6
b) 24 root 3 all over 5

Q14. ii) -3/ 2 plus minus (root 15)/2 i

b) ii) pi /4

c ii) 150 M ln (5) all over F hours

Q16 c) x all over (1 + ln x) + C

again, reiterating these are merely my answers and I didn't have time to check at all

if this helps you finish quicker, then go ahead and use it. otherwise dw

 

[faisalabdul16]

Anyone else nervously waiting for solutions to come up?

 

[aDimitri]

Anyone else nervously waiting for solutions to come up?

don't think i really need them now, just curious about his soln. to circle geo.
i'm down to 94/100 :/ so many silly mistakes. and a 2 mark reading error

 

[billym]

don't think i really need them now, just curious about his soln. to circle geo.
i'm down to 94/100 :/ so many silly mistakes. and a 2 mark reading error

What's the reading error? Depending on the circumstances, if you're lucky you won't be penalised.

 

[aDimitri]

What's the reading error? Depending on the circumstances, if you're lucky you won't be penalised.

14bii.
found the value of theta for which Fi was minimum not maximum. 0/2

 

[Carrotsticks]

Am I just throwing a big derp, or is Q15 (a) the hardest question in the paper? All my inequality signs are the wrong way around.