Let S be the circle in the xy-plane defined by the equation x² + y² = 4.
Let S be the circle in the xy-plane defined by the equation x² + y² = 4. Let P be a point on the circle S with both coordinates being positive. Let the tangent to S at P intersect the coordinate axes at the points M and N. Then, the mid-point of the line segment MN must lie on the curve