# Search results

1. ### Is it true that you don't always do as bad as you think you have?

Yeah, reckon I screwed up Eng Adv. Then I checked the HSC mark and which percentile it equates to. Then I realised I'm fine, considering my internal rank gives me an assessment mark of about 91-2. :)
2. ### Differentiating Logs and Exponentials help!!!!

Of course. OP, whenever you have a function of a function, the chain rule must be used. I just did it more systematically so you'd understand.
3. ### Differentiating Logs and Exponentials help!!!!

\frac{d}{dx}(ln(\frac{x}{x^{2}+1})) \\ \\ \text{When differentiating logs, it's just} \frac{d}{dx}ln(f(x)) = \frac{f`(x)}{f(x)} \\ \text{So first we differentiate} \frac{x}{x^{2} + 1}, \text{ using the quotient rule, which gives us:} \frac{1-x^{2}}{({1+x^{2})^{2}}{}} \\ \\ \text{And then we...
4. ### Locus question help!

The focus is (0,a). So find the line which foes through Q and (0,a) and that's your focal chord.
5. ### Any famous IMO peeps or something who are expected to state rank top 5?

A guy from our school has a pretty good chance at getting first this year. Hopefully we can top 2 years in a row. :p
6. ### Technically were we supposed to have "environmental policies" for Q28??

They don't. Refer to the above post.
7. ### Technically were we supposed to have "environmental policies" for Q28??

You could've said a lot for Q28, as long as you had more than 1 or 2 policies, it's fine to leave others out.
8. ### lorenz curve

It was just 1 mark, don't beat yourself up over it.
9. ### Mark predictions

1: 14/15 2: 14/15 3: 13/15

Easy exam.
11. ### Integration

Use the identity: tan(2x) = 2tanx / [1 - tan^2(x)] to simplify the expression and it is much easier. You should get 1/2 - tan^2(x)/2 after simplifying which is easy to integrate.
12. ### How do I do this integral?

Okay, thanks for that!
13. ### Will these cirlce geometry abbreviations be penalised in the HSC exam?

You can definitely use those abbreviations.
14. ### How do I do this integral?

Hey guys, How do I do this integral? \int e^xln(x) What I do is: \int e^xln(x)dx\\ \\ =e^xln(x) - \int e^xx^{-1}dx \\ \\ = e^xln(x) - \left [ e^xx^{-1} + \int e^xx^{-2}dx\right ] \\ \\ = e^xln(x)- \left [ e^xx^{-1} + e^xx^{-2} + 2\int e^xx^{-3}dx \right ] \\ \\ = e^xln(x)- \left [ e^xx^{-1}...
15. ### Hardest Trial

The question 6 in that paper wasn't even a very hard question - in fact it wasn't even the last question of the 1993 (i think) paper, it was Q7. I'm thinking like the top 25% of the state could get the last questions in this.
16. ### Is chatswood library crowded?

Chatswood is always crowded. Try UTS/USYD/State. Macquarie is usually fairly crowded but you can still get places to study.
17. ### Which school's maths trial paper best reflects the difficulty of the HSC exam?

Most do, that's the point of the trial exams, but I think that Sydney Grammar does it pretty well.
18. ### 4U Maths, or continue with Chem?

Can't you do 13 units? That way, if you want to drop your 4th unit of maths, or Chemistry, you can when you really know what you want to do. It beats asking people you don't know and don't know you over the internet.
19. ### trig question

cos(5x) = cos(2x)\\ \\ \text{using the general solution:} \\ \\ 5x = 2n\pi \ \pm \ 2x \\ \\ \therefore 7x= 2n\pi \ \ or \ 3x = 2n\pi \\ \\ so \ x = \frac{2n\pi}{7} \ or \ x = \frac{2n\pi}{3}
20. ### Is ionization and dissociation the same thing?

Nope they're different. When you talk about dissociation, a molecule can break into different (either charged or neutral) species. For example AB ---> A + B Whereas for ionisation, the molecule MUST break down into ions. For example AB ---> A+ + B- Ionisation is a form of dissociation.