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Finding the Parametrized curve

  1. Oct 4, 2009 #1
    Question: Attached.


    I know I have to find P1 and p2 depending on x and L to satisfy

    ax^2 + bxy + cy^2 + dx + ex + f =0

    I have tried looking at the ladder when resting on axis to get a better picture but cannot see where to go next.

    Attached Files:

    • dg2.bmp
      File size:
      223.2 KB
  2. jcsd
  3. Oct 4, 2009 #2


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    You don't want to start with the general equation of a conic because you don't know ahead of time it even is a conic. I know, the question tells you that, but you shouldn't assume it.

    Here's a picture of the slanted ladder:


    Figure out a and b in terms of x, L, and λ. You will need to use the trig functions of θ which you can also get in terms of x, L, and λ. That should get you started.
  4. Oct 5, 2009 #3
    Thanks so much! I am going to work more on this today after class.
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