The displacement vector of a particle of mass m is given by  r(t)  = i A cos⁡ωt + j B sin⁡ωt

Q: The displacement vector of a particle of mass m is given by $ r(t) = \hat{i} A cos\omega t + \hat{j} B sin\omega t $

(i) Show that the trajectory is an ellipse

(ii) Show that F = -m ω2 r