Chapter 5.3, Problem 23E

(a)

To determine

The effect of the forcing function $f\left(t\right)=\cos 1.9t$ on the initial value problem $d^{2}x/d{t}^2+4x=f\left(t\right),x\left(0\right)=0,dx/dt\left(0\right)=0$ and the difference between the result obtained and the result of Example 5.12. Also to compare the number of beats per unit time in these two functions.

(b)

To determine

The effect of the forcing function $f\left(t\right)=\cos 2.1t$ on the initial value problem $d^{2}x/d{t}^2+4x=f\left(t\right),x\left(0\right)=0,dx/dt\left(0\right)=0$ and the difference between the result obtained and the result of Example 5.12. Also compare the number of beats per unit time in these two functions.