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Really simple question, but I'm having trouble grasping this

  1. Mar 18, 2012 #1
    Why is the area of the cardioid r = 2sinθ-2 in the first quadrant represented with limits from π to 3π/2 and not with limits from 0 to π/2? Isn't the first quadrant 0 to π/2?
     
  2. jcsd
  3. Mar 18, 2012 #2
    r is negative (or zero) for all values of theta, so when theta is between pi and 3 pi / 2, (r, theta) is in the first quadrant.
     
  4. Mar 18, 2012 #3
    Actually, never mind, I'm still not understanding this :(
     
    Last edited: Mar 18, 2012
  5. Mar 18, 2012 #4
    Try plotting the point for theta = 5 pi / 4. Maybe you will see it then.
     
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