What is the wheel resolution function? How to get the analytic formula of circle

Where point (a, b) is the center of the circle and r is the radius.

A circle is a set of points whose distance from a fixed point is equal to a fixed length.

Then assume that the coordinates of the fixed point (that is, the center of the circle) are (a, b) and the fixed length (that is, the radius) is R.

Set the fixed point (x, y)

Then the distance from point (x, y) to (a, b) is equal to the radius r.

that is

√[(x-a)？ +(y-b)？ ]=r

Both sides are squares, understand?

(x-a)？ +(y-b)？ =r？

Extended data:

Various analytical formulas

The simplest equation of a circle: (generally, it is not necessary to take the coordinate origin as the center)

X' 2+y' 2 = r' 2, center o (0,0), radius r;

Standard equation of circle:

(x-a) ` 2+(y-b) ` 2 = r` 2, center O(a, b), radius r.

General equation of circle:

x ` 2+y ` 2+Dx+Ey+F = 0(D2+E2-4F & gt； 0), the center of the circle is (-D/2, -E/2), and the radius is (1/2)*√(D`2+E`2-4F)?