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Homework Help: Thin lens equation

  1. Aug 8, 2006 #1
    I am stuck on this problem because it been like 6 yrs since i took geometry and its due by 9 am. please help!

    Derive the thin lens equation:

    1/object distance + 1/ image distance = 1/focal length

    for a divergent lens, using a diagram of a divergent lens (hint: use similiar triangles)

    I have no idea where or how to start. please show me how to do it. I know the focal length for a diverging lens is always negative and always produces a virtual image.
  2. jcsd
  3. Aug 8, 2006 #2


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    Staff Emeritus
    Science Advisor

    Please ask well before the HW deadline, which was due in 5 hrs and 13 min at time of OP.

    For future reference - http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/lenseq.html
  4. Aug 8, 2006 #3


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    Staff: Mentor

    Now how in the heck did you know that? No wonder you're the GURU! :biggrin:
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