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Just try 2U Maths and drop to Standard if it's too hard. Probably around the end of Year 11/start of Year 12. Mark percentages don't really mean anything without context, as 50% at a top school might be better than 95% at a bad school.

The iron (II) cation in hydroxide produces a GREEN precipitate - https://en.wikipedia.org/wiki/Iron(II)_hydroxide The iron (III) cation in hydroxide produces a BROWN precipitate - https://en.wikipedia.org/wiki/Iron(III)_hydroxide

One approach is to express \tan(\alpha+\beta+\gamma) in terms of \tan\alpha, \tan\beta and \tan\gamma by using the angle sum formula twice. You can show that \tan(\alpha+\beta+\gamma) = \frac{\tan\alpha+\tan\beta+\tan\gamma-\tan\alpha\tan\beta\tan\gamma}{1-(\tan\alpha\tan\beta +...

It's ultimately up to you, but 10 units means less work/study, while 12 is safer if you screw up a subject. General Maths always scales poorly. In the 2017 HSC, an HSC mark of 95 (top 1%) in General Maths was scaled down to around 85. But anything below the top 5% will severely impact your...

Hydroxide precipitates are useful for identifying copper and both iron cations (especially for the latter if you aren't given thiocyanate or ferricyanide ions). Your school should certainly have sodium hydroxide available. $Cu(OH)_2$ is blue, $Fe(OH)_2$ is green, and $Fe(OH)_3$ is...

Unfortunately there's no way to get around the fact that you need to memorise. Either you memorise all the solubility rules or you memorise tests for the specific ions required by the syllabus. e.g. sulfate and phosphate both precipitate with barium, but barium phosphate dissolves under acidic...

Be careful... You should not conduct a flame test with lead ions (for obvious reasons). On a side note, it would be best to know at least one non-flame test for cations. You can also memorise some anion tests, such as adding a certain solution to check for a certain ion.

Not true. If your teacher makes you do it then they are wrong. In particular, \frac{dy}{dx} = \lim_{\Delta x \to 0} \frac{\Delta y}{\Delta x} (as the Cambridge textbook states when introducing the derivative) So the two are subtly different things - \Delta y is a change in y , but dy is...

Re: HSC 2018 MX2 Marathon $Let$\, I_n = \int_0^{\frac12} \frac{(\tan^{-1}2x)^n}{4x^2+1}\,dx\,$for$\,n\in\mathbb{Z}^+. $i) Show that$\, I_n =\frac{1}{2(n+1)}\left(\frac\pi4\right)^{n+1} $ii) Hence show that$\, I_0 \times I_1 \times I_2 \times ... \times I_n =...

It always comes down to your subject performance rather than the subject scaling. Except maybe if you chose a horrendously scaled lineup such as Aboriginal Studies, English Standard, Senior Science... As for choosing the 12th unit you might consider SoR 2U (if your school offers it) or a...

Part of the 3U course includes "Harder Applications of HSC 2 Unit topics", so yes you can be assessed on financial mathematics (see 1998 3U Q2b) and anything else in the 2U course. But it is far less likely to appear in a 3U paper than in a 2U one.

If the line is x = c \implies x-c=0, then there is no y (or more precisely, the co-efficient of y is zero). How could you make your equation's y co-efficient be zero?

Re: HSC 2018 MX2 Marathon a) \begin{aligned} I_1 &= \int^{\frac\pi4}_0 \tan \theta \,d\theta \\ &= \left[\phantom{\frac\,\,}-\log \cos\theta\right]^{\frac\pi4}_0\\&=\log 1 - \log \frac{\sqrt2}{2} \\ &= \log \frac{2}{\sqrt 2} \\ &= \frac12\log 2 \end{aligned} b) \begin{aligned} I_n +...

I still haven't figured it out yet... hints or a solution would be helpful.

From Patel 4U (Ex. 8B, Q5): $A missile is fired from$\, O\, $with initial velocity$\, U\, $at an angle$\, \alpha\, $with the horizontal.$\\\\$ Prove that it describes a parabola of focal length$\,\frac{U^2\cos^2\alpha}{2g}\,.\\\\ $Also prove that any point$\, P(x,y)\, $within and on the...

Quite odd, as the external exam includes 5 minutes of reading time and your exams should be prepping you for it. If you want to, you might like to take a few minutes regardless to skim over the test paper.

Looks like you should focus on 3D trig then. Harder questions like from Cambridge or Fitzpatrick would be good practice (I can send you the textbooks if you don't have them). You did well in the other topics, though - that's good. I think you would probably benefit from general advice on how...

Don't be too depressed - your marks right now have ZERO impact on your HSC. I went from 40% on my first 3U test to 95% in my most recent one. What were your mistakes in the exams? Too slow? Couldn't figure out how to do a specific problem? Poor algebraic manipulation skills?

How did you work out 1.45?

The area of the quadrant is: A = \pi r^2 \cdot \frac 14 The area of the triangle inside is: A = \frac12 bh And the area of the minor segment is the area of the quadrant less the area of the triangle.