Circle and equation formula All of them!

Circle and equation formula All of them!

The general equation of circle: X & # 178; + Y & # 178; + DX + ey + F = 0; (D & # 178; + E & # 178; > 4F)
The standard equation of circle: (x-a) &# 178; + (y-b) &# 178; = R & # 178;
The parametric equation of circle: x = a + RCOs θ; y = B + rsin θ (θ is the parameter)
Tangent equation of a circle:
The tangent of the circle passing through a point (x0, Y0) on the circle X & # 178; + Y & # 178; + DX + ey + F = 0 is
x0x+y0y+½(x+x0）+½(y+y0)+f=0
The tangent equation of the circle passing through the circle X & # 178; + Y & # 178; = R & # 178; the circle of the previous point (x0, Y0): x0x + y0y = R & # 178;