Exercise 5.3: response to an external force

Ass an external driving force $F(t)=F_{0}\cos {\omega t}$ to particle 1. plot $u_{1}(t)$ and determine its maximum steady state amplitude $A(\omega )$ for each value of $\omega$. Confirm that near a resonance $A(\omega )$ exhibits a rapid increase with $\omega$, and $u_{1}(t)$ increases without bound at the resonant frequency. Determine the resonant frequencies for the pairs of $k$-values already considered in parts 2-4 in Exercise 5.2. How do these values of $\omega$ compare to those in the previous exercise?