• Congratulations to the Class of 2024 on your results!
    Let us know how you went here
    Got a question about your uni preferences? Ask us here

Search results

  1. Affinity

    harder 3u and mechanics

    hey, induction: 2k+3>2* sqrt{(k+1)(k+2)} can you just square this and move it to the other side to make it >0 If they don't require you to use induction, for example: "By mathematical induction or otherwise" x,y>0, {(x+y)/2}^n or = 1 <=== don't quite get this prove by induction: for n>or =...
  2. Affinity

    simple perms n combs question.

    case bash case 1: atmost 1 I in the word ---> 8*6*7*5 case 2: 2Is in the word -> 7*6 * 4*3 add them together
  3. Affinity

    Really Hard harder 3unit :O

    They are classic questions.. very classic... Usually what they do for q8 is to take something classic like this and specialise it to some case...
  4. Affinity

    Success without tutoring for MX2?

    you don't need a tutor.. you just have to approach it the right way
  5. Affinity

    FINS2624 - What the fuck

    shit course teaches you jackshit especially when you get the lecturer who teaches out form his little how to do excel book. If I want to learn some maths I would do a maths course not a finance course...
  6. Affinity

    complex numbers question

    (z1)i = z2
  7. Affinity

    Really Hard harder 3unit :O

    you aren't reading carefully enough.. You were supposed to make integral of B_1 0, what you did was setting the value of B_1 at 1 to 0
  8. Affinity

    Harder 3u/probability

    i. easy ii.slightly sneaky argument. L_{k+1} has to go in one of the first k envelopes. suppose it goes into E_{n}. Then you are left with k letters and k envelopes.. Then you break it up into 2 cases.. a) L_{n} goes into E_{k+1} b) L_{n} doesn't go into E_{k+1} the first case (a) gives u_{k-1}...
  9. Affinity

    Vectors..

    I will use z and w for z1 and z2 and z' w' to denote their conjugates (z+w)/(z-w) = (z+w)(z'-w') / |z-w|^2 = (|z|^2 - |w|^2 - zw' + wz') / |z-w|^2 ----since |z| = |w|----- = (wz' - zw')/|z-w|^2 = [wz' - (wz')']/|z-w|^2 which must be pure imaginary because it's the difference between a number...
  10. Affinity

    root of unity question?

    it's false.. the sum is either 0 or n. [1-w][1+w^1+w^2+.......w^(n-1)] = 1-w^n = 0 so if w is not 1, then 1-w is not 0 so [1+w^1+w^2+.......w^(n-1)] must be 0, else the sum is n.
  11. Affinity

    integrate

    It's not an elemetary integral. You can reduce it to the partial perimeter of an ellipse and look up a table.
  12. Affinity

    ind 2008 q4 b) ii)

    Q has coordinates (-acos@,-bsin@) the tangent line at P is (x - acos@)(-b cos@)/(a sin@) = (y - bsin@) simplifies to (a sin@)y + (b cos@)x = ab now R = (-acos@, b(1 + cos^2 @)/sin@) So QR = [b(1 + cos^2 @)/sin@ ]+ bsin@ = 2b/sin @ using that as base, the correspnding height would be...
  13. Affinity

    poly question

    There was a comment after that "after multiplying through by a^(n-2). you have something similar with b. now add the 2 equations up and rearrange." for example if you nultiply that equation by a, you get a^3 - a^2 + a = 0
  14. Affinity

    probability

    there are 11 alphas and betas all together. the probability of a particular one coming first is 1/11 and there are 6 alphas. so 6/11
  15. Affinity

    Goedel's Proof

    If you need something a little more comprehensive "Friendly Introduction to Mathematical Logic" Christopher C. Leary:
  16. Affinity

    probability

    i) method one: There are 15! arrangements (imagine the letters are all different first)... if you assign equal probability to these.. you will see that the probably that an alpha comes before a beta is 6/11 so you get 15! * 6 / 11 then divide by (4!5!6!) to mod out the permutations to get...
  17. Affinity

    poly question

    i. You should be able to do this. ii. since a^2 - a + 1 = 0, you have a^n - a^(n-1) + a^(n-2) = 0 after multiplying through by a^(n-2). you have something similar with b. now add the 2 equations up and rearrange. iii. check the first 2 cases, then work on part ii's recurrence formula.. you will...
  18. Affinity

    2005 HSC Q8a

    yes but that is not the point.. the argument goes: Since ln is a monotonic, strictly increasing function, the x minimizing ln(f) is the same as the one which minimizes f.
  19. Affinity

    2005 HSC Q8a

    Best way to do the question is to take logs first.. minimizing f is same as minimizing ln(f) = ln(a+b+x) - ln(x)/3 + ln(constant) differentiating gives 1/[a+b+x] - 1/[3x] not hard to get x = (a+b)/ 2 from there. the 2nd derivative is -1/[a+b+x]^2 + 1/(3x^2) and if you substitute x = (a+b)/...
  20. Affinity

    Question abt QMB

    Go study it yourself.
Top