question_answer

Displacement of particles in a string stretched in the x-direction is represented by y. Among the following expressions for y, those describing wave motion are:

A) \[Cos\,kx\,Sin\,\omega t\]

B) \[Cos\,(kx\,+\omega t)\]

C) \[{{k}^{2}}{{x}^{2}}-{{\omega }^{2}}{{t}^{2}}\]             

D) \[Cos\,({{k}^{2}}{{x}^{2}}-{{\omega }^{2}}{{t}^{2}})\]