It is known that P is the upper moving point of the original x ^ 2 + y ^ 2 = 16, and point a (12,0) is the locus equation of the midpoint of the line segment when P moves on the circle o(∩_ ∩)o...

It is known that P is the upper moving point of the original x ^ 2 + y ^ 2 = 16, and point a (12,0) is the locus equation of the midpoint of the line segment when P moves on the circle o(∩_ ∩)o...

Let B (x, y) be the midpoint of the line segment, P (x1, Y1)
x=1/2(x1+12) y=1/2(y1+0)
We get X1 = 2x-12, Y1 = 2Y
And X1 ^ 2 + Y1 ^ 2 = 16
So (2x-12) ^ 2 + (2Y) ^ 2 = 16
That is, (X-6) ^ 2 + y ^ 2 = 4