Consider the ODE given by: x''(t) + c x'(t) + k x(t) = r(t). For c = 1 and k = 4, plot the position and velocity over the time interval [0, 20] seconds for the following cases. Analyze and discuss each result. Compare the two results.
1) r(t) is zero, x(0) = 1, x'(0) = 0.
2) r(t) is zero, x(0) = 0, x'(0) = 1.