A wave on a string is described by

D$($ x$,$ t $)=(3\mathrm{.}4$cm$)$ sin$[2$$($x$/(8\mathrm{.}4$m$)+$t$/(0\mathrm{.}12$s$)+1)]$

$,$ where x is in m and t is in s$.$

What is the wave speed?

What is the frequency?

What is the wave number?

At t$=0\mathrm{.}24$s$,$ what is the displacement of the string at x$=4\mathrm{.}9$m$?$