Intersection between two circles (2)

Given O1(x1,y1,z1), O2(x2,y2,z2), the center of the circles and r1 and r2, their Radius

Given M(x,y,z) the intersection, then another way is ...

O1O2 > r1 + r2

O1O2 < (r1 - r2) and (r1>r2)
NB.: what if r1 = r2 ?

O1O2 = r1 + r2

r1 - r2  < O1O2 < r1 + r2

r1 - r2  < O1O2 < r1 + r2

r1 - r2  < O1O2 < r1 + r2

NB. : when you see " = 0 " in Maths, you translate into "< Epsilon" in Computer