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  1. barbernator

    Hard maths question

    t=24 i think. ill put up my answer and see what u guys think
  2. barbernator

    LOOKING FOR CONICS/POLYNOMIALS RESOURCES

    don't you have a textbook?
  3. barbernator

    NEED HELP WITH MX 2

    school ranking has no effect on your mark in the test. If you come first and get a certain good mark, u get that mark no matter what. And also, even though it scales to be equivalent to 99+ atar, that is just for 2 units, you need to do well in the other 8 to get 99
  4. barbernator

    complex numbers

    i mean this info and solutions to z²+(2+i)z+2-2i=0 are i and -2-2i.
  5. barbernator

    complex numbers

    ahh yes good point missed that, also, is there an alternative solution to this that uses the other info, or is that just superfluous?
  6. barbernator

    Parametric equations question

    no worries :)
  7. barbernator

    Parametric equations question

    <a href="http://www.codecogs.com/eqnedit.php?latex=x^2=4ay\\ y=\frac{x^2}{4a}\\ y'=\frac{x}{2a}\\ at~P,~y'=t\\ therefore~the~gradient~of~the~normal~is~m=\frac{-1}{t}\\ point~grad~formula\\ y-at^2=\frac{-1}{t}(x-2at)\\ y-at^2=\frac{-x}{t}@plus;2a\\ yt@plus;x=at^3@plus;2at~-(1)\\...
  8. barbernator

    Parametric equations question

    one normal will have s's in it, one normal will have t's in it. When you solve them simultaneously, your answers will have both s and t's in them. When you solve simultaneously, you are trying to find x and y both in terms of s and t. It is in the second step that you are finding a relationship...
  9. barbernator

    Parametric equations question

    i will give you some steps for the answer, and then come back in a bit, and if you haven't got it by then i will post the answer/. 1. Find equations of both normals 2. Find intersection of normals by subtracting equations from each other 3. once you have subtracted equations, factorise both...
  10. barbernator

    Sequences and Series help?

    <a href="http://www.codecogs.com/eqnedit.php?latex=\frac{9(1-(2/3)^{4})}{1/3}" target="_blank"><img src="http://latex.codecogs.com/gif.latex?\frac{9(1-(2/3)^{4})}{1/3}" title="\frac{9(1-(2/3)^{4})}{1/3}" /></a>
  11. barbernator

    Sequences and Series help?

    a) although this is a geometric progression, for this part it is easies to do this I added 9+6+6+4+4+2.67+2.67 like you did. The way to put it into the formula is to take a=9, r=2/3 n=4. Multiply this answer by 2, and then subtract 9. This is because in the motion it moves up and down, doubling...
  12. barbernator

    Maths raw marks

    well done :)
  13. barbernator

    complex numbers

    circle with centre (-2,-3) and radius 1. post working in a sec <a href="http://www.codecogs.com/eqnedit.php?latex=|z^2-(12i-5)|=|z-(2@plus;3i)|\\ |(z@plus;(2@plus;3i))(z-(2@plus;3i))|=|z-(2@plus;3i)|\\ |z@plus;(2@plus;3i)||z-(2@plus;3i)|=|z-(2@plus;3i)|\\ |z@plus;(2@plus;3i)|=1\\...
  14. barbernator

    WHAT SHOULD I DO IN YEAR 12

    haha i know its true, but definitely wishful thinking
  15. barbernator

    WHAT SHOULD I DO IN YEAR 12

    HSC exam experience for accelerated students. I did 2u and 3u accelerated last year and fucked up one exam, but u can just do it again next year. Definitely worth it :)
  16. barbernator

    Amphiprotic/amphoteric

    yep, exactly :) remember to have equations so prove it
  17. barbernator

    Amphiprotic/amphoteric

    amphoteric substances just act as a base in some instances, and as an acid in other instances, there is no restriction upon what type of reactions they have. The example I used just happens to include 2 neutralisation reactions because it is the easiest one to remember :)
  18. barbernator

    Amphiprotic/amphoteric

    nope they are different. Amphiprotic means that a substance can either be a proton acceptor or proton donator. i.e. hydrogen sulfate, HSO4-. This can either accept a proton to become H2SO4, or donate a proton to become SO4 2-. Amphoteric substances are substances that can be act as either an...
  19. barbernator

    variations in gravitational field

    So yes, at the poles, g is the greatest. At the equator, g is the smallest, and this is due to the earths rotation. The earth is a fraction larger at the equator due to the tangential inertia of the mass at the equator forcing the earth "outwards" (why people get confused with centrifugal...
  20. barbernator

    Lewis electron dot structures and ionic compounds

    yeh they do, i meant split the aluminium up that was on the right side of the equation. and yes put one either side.
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