# Recent content by sharky564

1. ### HSC Chemistry Exam Solutions / Thoughts

I mean same, but x(x+10^-7)/(0.20-x), and the resulting quadratic has coeff for x 4.3E-7 x as opposed to 3.3E-7 x
2. ### HSC Chemistry Exam Solutions / Thoughts

There was a question which you had to determine the pH of a solution given the Keq was something of the order 10^-7, and the pH was like 10.smth. To do that q accurately, you had to have the initial concentration of [OH-] in pure water to be 10^-7, otherwise your quadratic is a bit off. I don't...
3. ### MX2 Integration Marathon 2021

\displaystyle \int_0^{\frac{\pi}{2}} \dfrac{\ln \left ( a^2 \sin^2 (x) + b^2 \cos^2 (x) \right )}{a^2 \sin^2 (x) + b^2 \cos^2 (x)} \; \mathrm{d}x = \dfrac{\pi}{ab} \ln \left ( \dfrac{2ab}{a + b} \right )
4. ### BoS Maths Trials 2019

no, not quite, but close also, if i did maths all the time, i'd probably bomb out in my atar, so we'll see
5. ### BoS Maths Trials 2019

Everyone who's got experience in oly maths can confirm international maths olympiad is much harder than 4u maths. 4u maths - requires maybe a month or so to get good at oly maths - years of training required, thousands of hours doing maths
6. ### MX2 Integration Marathon 2021

That last section which results in a dilogarithm is entirely 4U-able, and you may see that if you try the Feynman in a slightly different way.
7. ### My solutions to the 2019 Mathematics Extension 2 Paper

Oh right, that makes sense. I'll edit that.
8. ### My solutions to the 2019 Mathematics Extension 2 Paper

No because that swapping is taken into account in 2^4 - 2
9. ### My solutions to the 2019 Mathematics Extension 2 Paper

No, what you're saying is you're either choosing any two of the 4 possible spots for one digit (e.g. you're choosing the last two digits to be 1 if your initial 2 digits are 2, 1) and iterating over all possible ordered pairs of numbers, meaning you also count the time you choose the first two...
10. ### My solutions to the 2019 Mathematics Extension 2 Paper

That counts codes like 2211 twice?
11. ### My solutions to the 2019 Mathematics Extension 2 Paper

Thanks! I've replaced the images with the pdf.
12. ### My solutions to the 2019 Mathematics Extension 2 Paper

Of course, I can make mistakes, so any errors found would be great. EDIT: Newest version now a file on google drive as my last edit caused it to become too large: https://drive.google.com/open?id=1U_buMWY-R6i_ti3HunPg9TbSj_o74zFR
13. ### BoS Maths Trials 2019

We're actually identical twins uh what?
14. ### Maths Extension 2 predictions/thoughts?

yo, if anyone could chuck us the paper, that'd be great
15. ### BoS Maths Trials 2019

Considering I had contributed to the paper, it obviously couldn’t be me.