Hello, If the position of a particle w.r.t time is given as X=Acos(t)exp(-at), and Y=Asin(t)exp(-at), then it is pretty clear that the particle is moving in concentric circles around the origin with decreasing radius. Is anything else ought to be stated in order to describe the motion of the particle? I mean, does it suffice, when asked to describe the motion of this particle, to simply state that its motion would be as I delineated above? In other words, what more can one learn, and say, about the particle's type of movement? Also, I have found that dx/dy = [y+a√(A^2exp(-2at) - y^2)] / [ay - √(A^2exp(-2at) - y^2)]. Is that correct and, if so, can it be further simplified?