(a) Find the general solution of the differential equation
\(\frac{\mathrm{d}^{2} x}{\mathrm{~d} t^{2}}+10 \frac{\mathrm{~d} x}{\mathrm{~d} t}+25 x=338 \sin t\)
(b) Show that, for large positive values of \(t\) and for any initial conditions,
\(x \approx R \sin (t-\phi)\)
where the constants \(R\) and \(\phi\) are to be determined.