Non-harmonic response of relativistic particle to driving harmonic force

We consider the properties of one-dimensional oscillations a relativistic particle under driving harmonic force. It is found that in general case speed are an infinite sum odd sinusoidal and even cosinusoidal waves. In limiting ultra-relativistic particle, they represent square wave. There also oscillation suppression for large values force amplitude particular its initial phase. this case, performs only drift motion. The topic addressed to undergraduates studying applications theory oscillations.