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Homework Help: Cant understand this solution in certain points

  1. Feb 2, 2010 #1
    on a circle with radius 1 there are two points one is static the other is
    distributed evenly on the circle (i dont know the proper english term)
    we sign X to be the hypotenuse on the circle

    find the density function of the variable X

    solution(i partialy understood it)the questions come after the photo

    they say that we take x to be an angle from o til pi/2
    we scan only the northern hemisphere because its symmetric.

    what is the curv graph represents
    what is t?
    what is the meaning of y<=t?
    why if they say that x should go from o til pi/2?
    in the probability function they put x fro 0 till arcsin t/2 where t goes from

    after this step they did the derivative to find the density function
    i understand that step
  2. jcsd
  3. Feb 2, 2010 #2


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    Science Advisor
    Homework Helper

    Hi nhrock3! :smile:

    (have a pi: π and a ≤ :wink:)
    (we usually say "uniformly", but "evenly" is also ok :smile: and we usually say "around a circle")

    No, I don't think x is the hypotenuse.

    It's a little difficult to tell, but I think x and y are angles

    (and what is t … is it a chord? :confused:)

    Let's call the fixed point A, the movable point X, and the centre O. And let B be the other end of the diameter AOB.

    Then I think x is the angle between the two points, which equals AOX, and y is the angle ABX.

    y is always x/2 (if you don't know that, you need to look at a geometry book).

    Carry on from there. :smile:
  4. Feb 2, 2010 #3
    you are correct its a hord not a hipottenuse
    but you didnt answer my questions?
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