this question is about damped and undamped oscillators

Question#6 [CLO-2; PLO-2; Q Marks-10] The displacement att) of on undamped oscillator of mass m > 0 on a spring with spring constant k ) 0 satisfies mx* + kx =0, x(0) =a, x'(0) =0. (o) Solve this initial value problem. (b) Show that the solution is periodic with period T. meaning that att+ DEMO. (c) For what times t does the oscilator pass through equilibrium