I: X and Y should be in one-to-one correspondence. After rotation, 1 X is not allowed to correspond to 2 Y value.

Or,

II: The tangent L passing through the intersection point A of Y = (4+6x-x 2-2) 0.5 with the Y axis cannot intersect with the straight line parallel to the Y axis after rotation.

In this way, it can be judged that when L rotates perpendicular to the X axis, it is the limit position of α.

This angle is equal to the angle θ between the tangent of the circle at point A and the Y axis.

Answer (0, √2)

C(3，0)

tanθ=√2/3，0 & lt； =α& lt； =θ

Namely 0

The fourth floor made a detour when calculating the angle.

See the picture.