Resonance in a driven string

A taut string of length L and mass m has its right end fixed while the left end is driven and moves harmonically:
y(t,0) = A cos Ωt,
y
(t,L) = 0.

The simulation computes the steady state solution and can be used to check how resonance happens when the driving frequancy is (nearly) one of the normal frequencies, i.e. , one of the frequencies of the standing waves that may appear in the string when both ends are fixed.