The trajectory equation of the center of a circle which is circumscribed to the circle x2 + y2-4x = 0 and tangent to the Y axis is () A. Y2 = 8xb. Y2 = 8x (x > 0) and y = 0C. Y2 = 8x (x > 0) d. y2 = 8x (x > 0) and y = 0 (x < 0)

The trajectory equation of the center of a circle which is circumscribed to the circle x2 + y2-4x = 0 and tangent to the Y axis is () A. Y2 = 8xb. Y2 = 8x (x > 0) and y = 0C. Y2 = 8x (x > 0) d. y2 = 8x (x > 0) and y = 0 (x < 0)

Let P (x, y) be the center of the circle tangent to y axis and circumscribed to C: x2 + y2-4x = 0, and R be the radius, then (x − 2) 2 + y2 = | x | + 2, if x > 0, then y2 = 8x, if x < 0, then y = 0, so D

The moving circle is circumscribed with the circle x + y + 4x + 3 = 0, and at the same time is inscribed with the circle x + y-4x-60 = 0. The trajectory equation of the center of the moving circle is obtained, and what kind of curve it is explained

The square of X + 2 under the root sign plus the square of Y, plus the square of X - 2 under the root sign plus the square of Y, is equal to nine. It's an ellipse question: answer: let the center of the circle be (x, y), and the distance from the center of the circle to the centers of the other two circles should be shifted. One side of the formula is circumscribed to reduce the radius of the circle, and the other side is eight minus the distance