Velocity of particle in SHM in terms of displacement x is given as v=ωA2−x2​⇒v=Aω1−A2x2​​⇒Aωv​=1−A2x2​​⇒A2ω2v2​=1−A2x2​⇒A2ω2v2​+A2x2​=1 . . . (i) As equation of ellipse is a2x2​+b2y2​=1 Eq. (i) is similar to the equation of ellipse. So, the graph between velocity and displacement is an ellipse.