If all circles passing through (1,1), (2,2) from the origin are tangent, then the trajectory of the tangent point is

If all circles passing through (1,1), (2,2) from the origin are tangent, then the trajectory of the tangent point is

If AB is connected, then the slope of AB line k = (2-1) / (2-1) = 1ab midpoint C (3 / 2,3 / 2) AB vertical bisector CD equation is: Y-3 / 2 = - 1 (x-3 / 2), i.e. x + y = 3 ∵ Center D on X + y = 3, let Center D (x0, - x0 + 3), tangent point m (x, y) ∵ OD & # 178; = om & # 178; + MD & # 178; = om & # 178; + AD & # 178;, i.e. x0 ^ 2 + (- x0 + 3

What is the inner common tangent of two circles? The outer common tangent?

The inner common tangent is that two circles are on both sides of the tangent, which is called the inner common tangent;
The common tangent is that two circles are on the same side of the tangent, which is called the common tangent