Basic Calc problem! Please answer asap!

whitch of agnesi problem) its a curve defined as follows. let O be the origin, let T be the point (0,1), and let m be the line through T parallel to the x-axis. Let C be the circle centered at (0,0.5) with radius 0.5. For any point P on the circle besides O and T, we draw a ray from O through P. let this ray intersex m at point X. we then draw the altitude from X to the line through P parallel to the x-axis. The foot of this altitude, point A, is on the witch curve. When we trace out the resulting points A for all possible P, and include point T, we get the witch curve. Find the Parameterization for it and a function f such that the witch curve is the graph of the function y = f(x)

Thanks SO SO much