wave equation Questions

The displacement $y$ of a particle in a medium can be expressed as $y=10^{-6}\sin (100t+20x+\pi /4)\text{m}$, where $t$ is in seconds and $x$ in meter. The speed of the wave is:

The displacement $y$ of wave travelling in the $x$ -direction is given by $y=10^{-4}\sin (600t-2x+\pi /3)$ metres, where $x$ is in metres and $t$ in seconds. The speed of the wave-motion in $\text{m/s}$ is:

A wave is described by $y(x,t)=0.005\cos (\alpha x-\beta t)$. If the wavelength and time period are $0.08\text{m}$ and $2.0\text{s}$ respectively, then $\alpha$ and $\beta$ are: