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  1. Affinity

    projectile motion

    x= 12t y = 16t -5t^2 and you know that when it hits the surface, 5y = x (incline = arctan(1/5)) (16t -5t^2)*5 = 12t 25t^2 - 68t = 0 t(25t-68) = 0 t = 0 gives the initial point.. so at pont of impact, 25t - 68 = 0 t = 68/25 = 2.72 x = 32.64 y = 6.528 so the distance up the ramp is 33.28
  2. Affinity

    Timing & Picking Questions

    1. You can probably improve on your understanding of the material 2. People tend to waste time at the beginning.. if you manage to work at the speed you were working at near the end of the exam throughout the whole exam then you will finish alot more.
  3. Affinity

    confusion with log integrals

    try deriving it by using the substitution (x - 1 ) = \frac{3}{2}(e^x - e^{-x})
  4. Affinity

    Studying for Question 7/8 type Problems

    Most people would recommend more practice.. but I thikn it's these things that you will need to develop, how to do it depends on how you learn: 1. Technical - algebraic manipulations, differentiation, integration etc, you'll need to be reasonably quick and not make mistakes with these. Practice...
  5. Affinity

    locus- find eqn of circle

    That's probably the best way without resorting to heavy machinery. alternatively you can find the equation of 2 perpendicular bisectors of the line segments joining 2 points and solving them to get the center.
  6. Affinity

    Is this way of the Simpson and Trapezoidal rule correct for HSC or not?

    Pretty sure you just need to write down the line with the substitution CORRECTLY.
  7. Affinity

    What are people up to in terms of their topics finished?

    If you understood what was going on, then 2 weeks revisiosn is enough
  8. Affinity

    intergration (95 2b part i)

    This is a special case of the Beta function, for positive integers m,n you can prove using integration by parts that B(m+1,n+1) = (int with limits 1-0) x^m(1-x)^n dx = m!n!/(m+n+1)!
  9. Affinity

    integration using trig substitutions? :S

    have you tried any of these intrgation question you posted ;P?
  10. Affinity

    polynomials

    P'(x) = x^3 - x^2 - 4x + 4 = x^2(x - 1) - 4(x - 1) = (x^2 - 4)(x - 1) = (x+2)(x-2)(x-1) so P'(x) = 0 for x =2,1,-2 P(1) = 23/12 + c P(2) = 4/3 + c P(-2) = c - 28/3 so P(x) > 0 for all stationary points (hence all x since P increases without bounds for large and small...
  11. Affinity

    More polynomials...

    1. Don't care about complex u's -> looking at real x's hence u's [- A +- sqrt(A^2 - 4(B-2))] / 2 now since A is positive, the negative sign with the square root results in a bigger absolute value if there's a real root for x, then |u| must be >= 2 want |[- A - sqrt(A^2 - 4(B-2))] / 2| >= 2...
  12. Affinity

    More polynomials...

    something along those lines (sqrt(|x|) - 1/sqrt(|x|) )^2 >= 0 then expand tidy up and consider the case when x < 0
  13. Affinity

    More polynomials...

    if you solve for u you get u = [- A +- sqrt(A^2 - 4(B-2))] / 2 besides the usual constraint that the discriminant is positive, you have an additional condition that would preclude some roots : |u| > 2 (think why) so the curve is A^2 - 4(B-2) = 0 you can get he straight line from the other...
  14. Affinity

    If you solve this limit you are a god among men.

    the limit is obviously 0 when it exists Should put this in extracurricular, out of scope for 4 u
  15. Affinity

    polynomials

    Differentiate to get P'(x) solve P'(x) = 0 then plug back into P(x), etc.
  16. Affinity

    Polynomials

    The only problem is that 1/w = conjugate(w) only when |w| = 1. So that doesn't work Minor detail: since (w =/= 0)
  17. Affinity

    Polynomials

    well this takes care of the hard part, the rest is just tidying things
  18. Affinity

    Math decision/dilemma

    "do you think I might be capable?" - No idea, don't have any info to make a guess. But you should do it
  19. Affinity

    Using the software R

    try something like floor(v/10,0)*10 for that.
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