Make two mutually perpendicular straight lines L1 and L2 through point P (2,4). If L1 intersects X-axis at point a and L2 intersects Y-axis at point B, find the trajectory equation of the midpoint m of line ab

Make two mutually perpendicular straight lines L1 and L2 through point P (2,4). If L1 intersects X-axis at point a and L2 intersects Y-axis at point B, find the trajectory equation of the midpoint m of line ab

Let the coordinates of M be (x, y), then the coordinates of a and B are (2x, 0), (0, 2Y) respectively, connecting PM, ∵ L1 ⊥ L2, | 2 | PM | = | ab |. And | PM | = (x − 2) 2 + (y − 4) 2, | ab | = (2x) 2 + (2Y) 2, ∵ 2 (x − 2) 2 + (Y − 4) 2 = 4x2 + 4y2