In the plane rectangular coordinate system, what is the coordinate of the symmetric point of point B (2,1) about X axis What are the coordinates of the symmetric point about the Y-axis and the symmetric point about the origin

In the plane rectangular coordinate system, what is the coordinate of the symmetric point of point B (2,1) about X axis What are the coordinates of the symmetric point about the Y-axis and the symmetric point about the origin

On the x-axis (2, - 1)
On the y-axis (- 2,1)
Origin (- 2, - 1)

In the plane rectangular coordinate system, the coordinates of point a (3, - 2) about the x-axis symmetry point B are_ The coordinates of the symmetric point c about the y-axis are_

B（3,2）C（-3,-2）

There is a point P on the ellipse x ^ 2 / A ^ 2 + y ^ 2 / b ^ 2 = 1, so that OP is perpendicular to AP (o is the origin, a is the endpoint of the long axis)

The ellipse x ^ 2 / A ^ 2 + y ^ 2 / b ^ 2 = 1 (a > b > 0) intersects with the positive half axis of X axis at point A. there is always a point P on the ellipse to make OP perpendicular to AP (o origin) for centrifugation
The ellipse x ^ 2 / A ^ 2 + y ^ 2 / b ^ 2 = 1 (a > b > 0) intersects the positive half axis of X axis at point A. there is always a point P on the ellipse to make OP perpendicular to AP (o origin) to find the range of eccentricity E

Take OA as the diameter of the circle, and point P is on the circle. With the decrease of E, the ellipse will be tangent to the circle. Circle: (x-a / 2) ^ 2 + y ^ 2 = (A / 2) ^ 2, the equation of simultaneous ellipse is (a ^ 2-B ^ 2) x ^ 2 / (a ^ 2) - ax-b ^ 2 = 0, the discriminant needs to be greater than zero and - a √ 2 / 2