Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Finding equation of a circle

  1. Mar 14, 2005 #1
    hi, this isn't really a physics problem, more of a math problem, however, i can't find a math forum.. so i thought i'd put it here :D

    your given that a circle passes through y-axis adn x-axis, also the circle passes through the points (8, -1).. find the equation of the circle, reminded that the equation should be in the following form: (x-h)^2+(y-k)^2=r^2

    i have no idea how i should approach this problem, thanks alot for your help :P
     
  2. jcsd
  3. Mar 14, 2005 #2

    SpaceTiger

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    What are the other points?
     
  4. Mar 14, 2005 #3
    that's teh whole question.. that's suppose to be the hardest problem on the sheet, and since there are no any other point, i can't figure it out :|
     
  5. Mar 14, 2005 #4

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    What do you mean my passes through "y" & "x" axis...?Shouldn't it be the other way around...?:wink: Actually,i think they mean that the circle is tangent to those lines...

    I found the radius to be either 8.5,or 0.5.You decide which value is correct...

    Daniel.
     
  6. Mar 14, 2005 #5
    mmm.. yes, it indeed is tangent to the x/y axis.. can you tell me how you got it? i care more about the process than the result :D thank you very much!
     
  7. Mar 14, 2005 #6

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    Draw a circle & use geometry in a pythagoreic triangle...

    Daniel.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook