Use the script for the nonlinear pendulum and change the value of $A$ in the function from $0\mathrm{.}0$ to $0\mathrm{.}9$ so that a driving force is on$.$

$($b$)$ Initialise a variable named transient $=5000$ in the script before the integration loop starts. This variable establishes the threshold for the transient motion which we wish to eliminate from the phase space graph. Your script should plot a graph of $(t)(t)$ only for $t>$

$t[$transient$],$ being $t[i]$ an array that stores time values sequentially on each of its components $i.$

$($c$)$ Run the script $.$ The pendulum is nonlinear and damping should be switched on $(k=0\mathrm{.}5).$

I've attached the code i used to plot theta, omega versus time for the damped nonlinear pendulum. Basically, if you start the pendulum evolution at t $=0$ and store example $10000$ points of this evolution in lists or arrays, you will plot in the phase portrait all points except the first $5000$ points corresponding to the transient stage.