Re: Reason for the Center of the Circle??

From: Ken Pledger (Ken.Pledger_at_mcs.vuw.ac.nz)
Date: 01/27/05 

Date: Fri, 28 Jan 2005 11:32:50 +1300

In article <1106802435.729286.46120@z14g2000cwz.googlegroups.com>,
 need4speed850@yahoo.com wrote:

> Ok, I have a question regarding the Center of a Circle. Now, in math
> classes around the world, a circle formula is taught to students. This
> formula is derived from the distance formula.
>
> (x-h)^2 + (y-k)^2 = r^2
>
>
> Great. Now here's my million dollar question:
>
> WHY IS THE CENTER OF THE CIRCLE (H,K)???
>
> Who picked those coordinates and WHY??? ....

      Are they all that common? If so, it's just a recent text-book
tradition. I've seen (u,v) used; and Salmon's notation

x^2 + y^2 + 2gx + 2fy + c = 0

corresponds to centre (-g, -f).

      FWIW, my own preference is (x_0, y_0).

            Ken Pledger.