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*sigh* pplz stop having fun...get offline and study!

but considering that u'd have to be good at maths to do maths enrichment / olympiad, this is the same as saying that ppl who're good at maths have an advantage...

the last bit about the irrationality was only one mark tho! and besides, about proving irrationality, it was done b4 with 'e' in 2001 4u. And that time there was significantly less 'leadup' questions.

figured the rest of Q8 out now... anyway, if you solve the quadratic x^2 - 4x + 3 + y = 0 (which comes from (x-1)(3-x) = y), then you should get: x = 2 +/- sqrt(1-y) so if the 2 solns are x1, x2, then the area we need is A = pi[(3-x1)^2 - (3-x2)^2] and if u let x1 = 2 - sqrt(1-y), x2...

erm definitely harder than last years (which is good to see, actually. You don't need to worry about silly mistakes). but most of the paper is definitely do-able. They've included a lot of mathematical content. the conics question is a biatch...quite a lot of algebra...but that is doable...

i wouldn'tve started at Q8 in 4unit exams... i think i did my 3u exam backwards, but i took a big big risk there...

actually, you'll need to be the top 20 in the state to get in...call that HD or whatever you like...

anyone doing it here?

they call it the rational root theorem if x = p/q is a rational root, then p divides the constant term, and q divides the leading coefficient.

err...lead is very malleable, i dun think ppl bother.

huh??? the question is prolly asking for all the isomers to a) di-bromo-ethane b) tri-bromo-ethane and they're not asking for complete reaction equations...

it's not how much extra-curricular you do, but how much you can talk about it. i think for me i built up some sort of recurring-type theme where i liked teaching because i liked helping people. (in actual fact i prolly like teaching because of the superiority-inferiority thing, but hey...

perhaps i should keep my grievances to myself, but when u go into the HSC with a paper like last yr's chemistry paper, the first thing u should think to urself is "fark, they're gonna screw me over with the scaling"

*ahem* chem scaling is NOT good...

the only difference between a co-ordinate covalent, and a covalent bond, is where the electrons came from. an oxygen radical is simply a single oxygen atom. It has an even number of electrons, yet it is a radical, because it is biradical (i.e. in the outer shell it has 2 paired and 2...

wtf?? well the physical properties you should have is: ozone: higher MP, BP, high aqueous solubility oxygen: low MP, BP, low solubility the reason is that ozone is polar (in the middle O atom, 3 pairs of e- are on one side), and so you'd expect high MP, BP, solubility.

Look, I dun think anybody has the solution yet, and btw, i can only find one, so i shall not be too greedy. 2 throws (or less): P(bob) = 1/4 + 3/4 * 1/4 = 7/16 P(penny) = 1/2 * 1/2 = 1/4 P(neither) = 5/16 Now of this 5/16, lets see the possible combinations: HT TT TH TT TT TT TT HT...

the catalyst is the acid (H+). But why sulfuric acid instead of HCl, HNO3, etc? besides the fact that SO4 is pretty much inert, conc H2SO4 is 'dehydrating' - it absorbs water. This is necessary to drive the equilibrium towards the ethene product. u can see this using le-chat's principle...

e- transfer rxns are those where the oxidation numbers of some of the atoms change during the course of the rxn.

to filter or not to filter... you have to consider which would cause you more error: the volume displacement caused by the BaSO4 (which to my recollection is waaay less than 1ml). Considering that the volumetric is at least 100mL (i can't remember if 100 or 250), that's less than 1% error...