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Homework Help: Help eqns of locus

  1. Mar 22, 2005 #1
    CHECK PLZ HELP a little

    Determine the equation of the following locus.

    1)-Locus of points that are 10 units from the origin.
    x^2+y^2=100?

    2-The points 3 units from the circumference of the circle with centre (0, 0) and radius 5 units
    What does the 3 units from the circumference mean? is the equation x^2+y^2=25?

    Are these two correct Im not sure about the second one?
     
    Last edited: Mar 23, 2005
  2. jcsd
  3. Mar 24, 2005 #2
    HELP! are my answers correct? :cry:
     
  4. Mar 24, 2005 #3
    it means 3 units from the circle. The question asks for the set of points a distance of three units from the circle defined by [itex] x^2 +y^2 = 25[/itex].
     
  5. Mar 24, 2005 #4
    [tex] x^2+y^2=8^2?[/tex] since the radius is 5+3?
     
  6. Mar 24, 2005 #5
    That's half of it.

    Here's a hint: think INside the box (or in this case, the circle!)
     
  7. Mar 24, 2005 #6
    and another locus is x^2+y^2=2^2

    I should simplify both of these to 4 and 64 right?
     
  8. Mar 24, 2005 #7
    Yep, that's fine~
     
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