1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Equation of circle in quarter/half of a circle

  1. Aug 28, 2010 #1
    1. The problem statement, all variables and given/known data

    I am curious why is the equation of a quarter of a circle ([tex]y = \pm \sqrt{r^{2}-x^2}[/tex]) the same as half a circle? Shouldnt they be different?

    2. Relevant equations

    n/a

    3. The attempt at a solution

    n/a
     
  2. jcsd
  3. Aug 28, 2010 #2
    If you want quarter circle you have to use either + (for positive quarter) and - (for negative quarter) in the equation you mentioned.
    For getting half circle both + and - ve values of equation are considered.
     
  4. Aug 28, 2010 #3

    Mark44

    Staff: Mentor

    Actually, they are different if you include restrictions on x. For example, the equation for the upper right quarter circle is
    [tex]y = +\sqrt{r^{2}-x^2}, 0 \le x \le r[/tex]

    The equation for the upper left quarter circle has a different restriction on x; namely
    [tex] -r \le x \le 0[/tex]

    For the upper half of the circle, you have [itex]-r \le x \le r[/itex]

    For the lower half circle and quarter circles, the only difference is that the negative square root is used.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Equation of circle in quarter/half of a circle
  1. Equation of a circle (Replies: 9)

  2. Equation of a circle (Replies: 11)

  3. Equation of circle (Replies: 6)

  4. Equation of a Circle (Replies: 2)

Loading...