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Homework Help: Algebra of two equal positive charges

  1. Feb 10, 2006 #1
    I need some help in finding a way to solve the following problems.:

    - Two equal positive charges q are on the y axis, one at y= +a and the other at y= -a.

    a) Show that the electric field on the x axis is along the x axis with
    Ex= 2kqx(x2 + a2)-3/2.

    b) Show that near the origin, when the x is much smaller than a, Ex is approximately 2kqx/a3.

    c) Show that for values of x much larger than a, Ex is approximately 2kq/x2. Explain why you would expect this result even before calculating it.

    Thanks for your efforts!
  2. jcsd
  3. Feb 10, 2006 #2
    You need to show your efforts before you get help. So, where do you think you should start?
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