Answer to Question #316198 in Differential Geometry | Topology for sket

Question

if P is any point on the circle C in the XY plane of a radius a>0 and centre(0,a ) ,let the straight line through origin and P intersect the line y=2a at Q and let the line trough P parallel to the Xaxis intersect the line through Q parallel to the Y axis at R.as P moves around C , R trace out a curve find its paramatrisation and its cartesian equation