Carrotsticks' 2017 Mathematics Extension 2 solutions (2 Viewers)

[calamebe]

Today, I learned that I can't count.

(cheers man)

Honestly, sometimes I feel like my genny friends can count to ten better than I can.

 

[Carrotsticks]

Honestly, sometimes I feel like my genny friends can count to ten better than I can.

I sure hope they can. I'm pretty sure they spend a whole term learning the integer sequence from 1 to 10.

 

[Carrotsticks]

Hey Carrotsticks, you reckon I would lose 1/2 marks if I got a = 1 and 1/3, but I didn't have the plus minus?

I don't even think you would lose any marks. Unless I am mistaken, even in the course it's not clear if A must be zero or not. If NESA can't decide then surely they won't dock you down for that.

 

[Jkass]

Hey Carrotsticks, what do you reckon the e4 cut off this year is going to be?

 

[Carrotsticks]

Weird, I fixed the locus diagram and then it stuffed up again.

 

[NinjaDatHSC]

Hey Carrot, can you check your DM's quickly

 

[raz999]

Is the answer to the conics one a=+-1, +-1/3?
I thought by definition, a>0

 

[Raeservoir]

That was impressively quick! Gonna ask my own question with a careless blunder (technically 2) I made: ellipse/hyperbola 15c.

- part i: pretty sure I did c^2 - a^2 instead of a^c - c^2 - my bad for not checking the proof in the question

- part ii: swapped + and - for hyperbola and ellipse eccentricities, so I did a^2 - b^2 and c^2 + d^2, which countered the mistake I made in part i allowing me to prove it.

Are these two mistakes worth -1 each? If so, unfortunate... they are technically 2 separate errors.

 

[SaltSolutionPromo]

Most of my cohort thought it was easy actually (my cohort is around 119 students). Essentially everyone I know who knows what they're doing thinks they got 90+ raw, and most of the top students (by top I mean top 40 lol) have lost maximum 5 marks so far.

 

[pikachu975]

Most of my cohort thought it was easy actually (my cohort is around 119 students). Essentially everyone I know who knows what they're doing thinks they got 90+ raw, and most of the top students (by top I mean top 40 lol) have lost maximum 5 marks so far.

Woah do you go like james ruse?

 

[SaltSolutionPromo]

Woah do you go like james ruse?

Sydney Boys actually

 

[Carrotsticks]

Okay I'm going to address the a=plus/minus versus a>0 issue.

We say a>0 to keep things simple. That is, so that we may assign a physical thing (length of semimajor axis) to the value of "a". But mathematically, this is not a restriction.

Q: Will I get penalised for not doing A=plus/minus ?

A: I don't think so. I reckon you'll be safe leaving it at 1/3 and 1.

 

[Carrotsticks]

That was impressively quick! Gonna ask my own question with a careless blunder (technically 2) I made: ellipse/hyperbola 15c.

- part i: pretty sure I did c^2 - a^2 instead of a^c - c^2 - my bad for not checking the proof in the question

- part ii: swapped + and - for hyperbola and ellipse eccentricities, so I did a^2 - b^2 and c^2 + d^2, which countered the mistake I made in part i allowing me to prove it.

Are these two mistakes worth -1 each? If so, unfortunate... they are technically 2 separate errors.

Nah you'll probably only lose one mark overall.

 

[SaltSolutionPromo]

But even in most years, we only get like 70-80 E4 out of 120 circa. Unless our cohort this year is stronger, which maybe the case since we had a 100% B6 rate on 2U accelerated last year.

 

[pikachu975]

https://scontent-syd2-1.xx.fbcdn.ne...=eaea7b71e683d45c848190d6160eb803&oe=59F06E15

Does this mean you get your entire exam marked by 6 markers or 1 per section

 

[Trebla]

https://scontent-syd2-1.xx.fbcdn.ne...=eaea7b71e683d45c848190d6160eb803&oe=59F06E15

Is this a new thing from NESA? That'll cost so much to pay the markers I thought they mark maths once?

There is a different marker for each question/section.

 

[ProfLayton2000]

Feelsgood when u remember mid-test q15 bii) is just q12a) of 2012 BoS trials

 

[jjHasm]

oops i thought i was getting 68-70, looking at solutions probably getting 60ish, what do you guys reckon this would moderate to? 85+?

 

[mkwon99]

what do u guys think 91-94 raw will get?

 

[same1111]

source? or is that just ur inkling