The third question: Substituting X and Y into β, it is found that the curve is that the sum of the distances from the moving point to two fixed points (3,0) and (-3,0) is four times the fixed value, and the root number is 3; It can be seen that curve C2 is an ellipse: a=2 times root number 3, b= root number 3, and c = 3；;

In addition, the distance from the point on C2 to (x0,0) is d, and d 2 = (x-x0) 2+y 2. Combining with C2 equation x 2/ 12+y 2/3 = 1, we can see that

D 2 = (12+3x2-8x * x0+4x02)/4, it is very simple to get to this step. The following is an analysis of this equation:

On the right side of the equation is a quadratic parabola with an upward opening, and its minimum value is the vertex: (9-x0 2)/3.

According to the conditions, the minimum value is not less than 2/ root number 3, so the minimum value of d 2 is not less than 4/3.

(9-x0^2)/3>； =4/3

The result is 0.