Chapter 4.6, Problem 19P

For the initial value problem in Problem 18, plot $y\text{'}$ versus $y$ for $\omega =0.7,\omega =0.8$, and $\omega =0.9$, that is, draw the phase plot of the solution for these values of $\omega$. Use a $t$ interval that is enough, so the phase plot appears as closed curve. Mark your curve with arrows to show the direction in which it is traversed as $t$ increases.