Question

Quick question

Answer 1

How is x² + y² - 2x = 0 a circle with a radius of 1 centered at (1, 0) ? Isn't the radius r^2, meaning the radius here should be 0? I must be missing something obvious :P

Answer 2

you can rewrite that to the more familiar circle form (x-h)^2 + (y-k)^2 = r^2

Answer 3

do you remember completing a square?

Answer 4

\[x^2-2x + y^2 = 0\]
complete the square for the x^2 - 2x
\[x^2 - 2x +1 + y^2=1\]

Answer 5

factor that
\[\large (x-1)^2 + y^2 = 1\]

Circle radius r, and center (h,k)
\[(x-h)^2+(y-k)^2 = r^2\]

Answer 6

you see it now?