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Q in parabola

  1. Apr 22, 2010 #1

    In this queation wich equation we use X^2 = 4ay or y^2 = 4ax and why ?

    A paraboloid is formed by revolving a parabola about its axis . A spotlight in the form of a parabolid 5 inches deep has it's foucs 2 inches from the vertex . Find to one decimal place , the raduis R of the opening of the spotlight ....
  2. jcsd
  3. Apr 22, 2010 #2
    Both equations represent the same relation. The names of variables have just been flipped. In the first equation the spotlight would be pointing along the y-axis. In the second equation it would be pointing along the x-axis.
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