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  1. airie

    A mixture (no pun intended) of Questions

    1. Concentrated H2SO4 is used as a catalyst in dehydration of ethanol to form ethene and water, we all know that. And that dilute H2SO4 can be used in hydration of ethene. But my teacher found some source saying that conc H2SO4 can used as a catalyst in hydration of ethene as well. Question is...
  2. airie

    Polynomial - common factor

    From Cambridge (year 12 textbook), Exercise 4E, Q14: Show that if the polynomials x3+ax2-x+b and x3+bx2-x+a have a common factor of degree 2, then a+b=0. How do you do it? I bashed around for a bit and only managed to get a=b, which obviously works. Thanks in advance :)
  3. airie

    Subjects contributing to UAI

    Say I'm doing 12 units, and 8 of these definitely count towards my UAI. As for the remaining two subjects, say I got 90 for subject A and 91 for subject B, both being final HSC marks. So my HSC mark for subject A is lower than that of subject B. But if the scaled mark for subject A is higher...
  4. airie

    Discovery Days?

    So, who else is going to the Discovery Days? Just got this postcard at school yesterday about it. It's organised by University of Wollongong, apparently you just go and experience a day as if you're a real uni student. Looks like you'd have to register before 30 Nov, and your school would give...
  5. airie

    Help?

    From Cambrudge Year 11 3u textbook, exercise 10F, Q11: Basically, it involves sketching the graph of x3+y3=a3 where a is a constant, but my graph looks different from that in the answers section. And I can't figure out why :o (Note: I'm assuming that a>0 here, same as the textbook. The sign...
  6. airie

    OK...what's this "moderated" business?

    This is what I understand on the calculation of your Internal Assessment mark: You are ranked for the subject among the other students in your year. You go and do the HSC external exam. They pool all the marks (aligned external assessment mark, where you keep your own mark for the external)...
  7. airie

    Eligibility for doing ESL

    Can anyone tell me who are eligible to do ESL for the HSC? I'm quite baffled at the moment :confused: See, I came here to Australia three and a half years ago, and by the time I do my HSC I would have come for more than five years, so I thought that I would not be able to do ESL. But recently I...
  8. airie

    A...Question :P

    OK actually don't really know where this question belongs...but here goes...:p Prove that for any integer n>=5 and for any convex n-gon, the arithmetic mean of its sidelengths is no greater than the arithmetic mean of its diagonals. How would you attack such problems? I only got up...
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