The mathematical model of a dynamic system is described by

\[4 \ddot{x}+4 \dot{x}+5 x=\frac{10}{3} u_{r}(t), \quad x(0)=0, \quad \dot{x}(0)=\frac{2}{3}\]

where \(u_{r}(t)\) is the unit ramp. Plot the response \(x(t)\) by

a. Using the lsim command over \(0 \leq t \leq 5\).

b. Simulating the Simulink model of the system.