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March 29, 2024, 01:38:41 pm

Author Topic: Compilation of solutions to HARD past HSC papers (4U)  (Read 22262 times)  Share 

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RuiAce

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Compilation of solutions to HARD past HSC papers (4U)
« on: June 16, 2017, 01:23:27 pm »
+13
Hi all,

As the thread title suggests, this thread will be reserved specifically for solutions to past BOSTES papers only. You should still post any other questions in the question thread, but please consider looking here if it is from a past BOSTES paper.

The main purpose of this thread is just so that if you have a really long answer, you won't need to go around asking for a solution but can just look for it here. Of course, you're always welcome to ask more about the solution if you're still confused :)

This is a work in progress and I've only decided to open it up now. I will most likely be opening up a thread for 2U and definitely one for 3U as well. I'll add more questions as more people ask them.
_____________________________________

2000
- Q8 a) i) Complex numbers and series

2001
- Q7 b) Hand-waving around polynomials and rational numbers
- Q8 b) Irrationality of \(e\)

2002
- Q7 b) Complex numbers, vectors and a pentagon
Parts i) and ii)



Parts iii) and iv



2005
- Q8 b) An arguably multifaceted question on a hyperbola

2008
- Q8 a) i) First of the urns question

2010
- Q4 c) Odd case of a quadratic in 4U

2011
- Q8 c) + d) Strange absolute values

2012
- Q15 b) i)-iv) Working around real roots
- Q16 c) i) First part of selecting integers

2013
- Q10 The hostel question

2014
- Q16 c) Surprising integral

2015
- Q16 b) Long winded complex numbers

"AN Final Revision 2017" contains:
- 2003 Q8b
- 2016 Q16b
- 2015 Q16b (Typo in the file)
- 2013 Q16b
____________________________________________

For papers from 2016 onwards, you can access handwritten solutions for the entire paper:
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
« Last Edit: November 15, 2021, 11:48:58 pm by fun_jirachi »

Wales

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Re: Compilation of solutions to HARD past HSC papers (4U)
« Reply #1 on: June 16, 2017, 01:25:46 pm »
+1
Would it be a good idea to start off with providing solutions to all the last questions for all 4u papers from 99-16? It seems they're usually the harder ones.

Just a thought.
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brenden

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Re: Compilation of solutions to HARD past HSC papers (4U)
« Reply #2 on: June 16, 2017, 01:27:25 pm »
+4
Looks awesome Rui, you legend!
✌️just do what makes you happy ✌️

RuiAce

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Re: Compilation of solutions to HARD past HSC papers (4U)
« Reply #3 on: June 16, 2017, 01:29:21 pm »
+2
Would it be a good idea to start off with providing solutions to all the last questions for all 4u papers from 99-16? It seems they're usually the harder ones.

Just a thought.
It takes time. Personally, I'm fine with people just posting their questions in the 4U questions thread and I'll (or Jake will) get to it afterwards.

If I have time after uni break I'll probably search up some solutions in the past as well. I'm sure there's been more than just that one derangement question that I've done before, which came out of the HSC and can be considered hard.

Wales

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Re: Compilation of solutions to HARD past HSC papers (4U)
« Reply #4 on: June 16, 2017, 01:31:11 pm »
0
It takes time. Personally, I'm fine with people just posting their questions in the 4U questions thread and I'll (or Jake will) get to it afterwards.

If I have time after uni break I'll probably search up some solutions in the past as well. I'm sure there's been more than just that one derangement question that I've done before, which came out of the HSC and can be considered hard.

Of course. That makes sense, sounds good.

This place is a blessing to us all.
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RuiAce

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Re: Compilation of solutions to HARD past HSC papers (4U)
« Reply #5 on: June 18, 2017, 07:49:43 pm »
+5
Imported a few more and a 3U thread should be opening up soon.

I found it quite funny when three in a row were perms and combs.

Wales

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Re: Compilation of solutions to HARD past HSC papers (4U)
« Reply #6 on: June 19, 2017, 11:29:48 am »
+1
The "surprising integrals" solutions doesn't lead to anywhere.
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jakesilove

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Re: Compilation of solutions to HARD past HSC papers (4U)
« Reply #7 on: June 19, 2017, 11:38:19 am »
+6
Rui mate this is the best idea ever. You will personally save the marks of hundreds of 4U students.
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Studying a combined Advanced Science/Law degree at UNSW

RuiAce

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Re: Compilation of solutions to HARD past HSC papers (4U)
« Reply #8 on: June 19, 2017, 10:43:56 pm »
+1
The "surprising integrals" solutions doesn't lead to anywhere.
Fixed. Somehow my search link got pasted in and not the actual link to the thread

RuiAce

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Re: Compilation of solutions to HARD past HSC papers (4U)
« Reply #9 on: September 28, 2017, 09:56:38 am »
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Following the video release, I've attached my content block "handout" in the opening thread. I may convert them to screenshots later, but for now the PDFs should be enough :)

frog1944

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Re: Compilation of solutions to HARD past HSC papers (4U)
« Reply #10 on: October 22, 2017, 12:02:49 pm »
0
Hi RuiAce,

I was curious for Q 16 a) i), why does sin(theta)=sin(-alpha) mean that theta = - alpha? Why don't you have to consider it in terms of general solutions, with theta = 2*pi*k - (-1)^k alpha, and then some how work it out from there?

Thanks

RuiAce

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Re: Compilation of solutions to HARD past HSC papers (4U)
« Reply #11 on: October 22, 2017, 12:26:52 pm »
+2
Hi RuiAce,

I was curious for Q 16 a) i), why does sin(theta)=sin(-alpha) mean that theta = - alpha? Why don't you have to consider it in terms of general solutions, with theta = 2*pi*k - (-1)^k alpha, and then some how work it out from there?

Thanks
What year are you talking about?

(Although, sometimes you can make assumptions about the domain of angles. Sometimes it makes no sense if theta falls outside the domains \(0\le \theta \le \pi\) or \(-\frac\pi2 \le \theta \le \frac\pi2\), and when that happens you can just jump straight to the answer without considering a general solution.)

frog1944

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Re: Compilation of solutions to HARD past HSC papers (4U)
« Reply #12 on: October 22, 2017, 12:28:44 pm »
0
Oh, sorry, HSC 2016 MX2.

RuiAce

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Re: Compilation of solutions to HARD past HSC papers (4U)
« Reply #13 on: October 22, 2017, 12:36:33 pm »
+3
Oh, sorry, HSC 2016 MX2.

Basically you just make the choices for alpha and theta in those specified domains, just like when you solved trig equations back in 2U. The general solution exists for when domains are unspecified.

frog1944

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Re: Compilation of solutions to HARD past HSC papers (4U)
« Reply #14 on: October 22, 2017, 01:53:33 pm »
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I don't understand. If -pi < x <= pi, -pi < y < pi, and sin(x) = 1/2 and sin(y) = -1/2, then couldn't x = pi/6, 5pi/6 and y = -pi/6, -5pi/6 . Then, couldn't x = pi/6 and y = -5pi/6, then x does not equal -y?