A wave on a string is described by

D$($x$,$t$)=(2\mathrm{.}8$cm$)$D$($x$,$t$)=(2\mathrm{.}8$cm$)$

sin$[2$$($x$/(8\mathrm{.}4$m$)+$t$/(0\mathrm{.}16$s$)+1)]$sin$[2$$($x$/(8\mathrm{.}4$m$)+$t$/(0\mathrm{.}16$s$)+1)],$ where xx is in mm and tt is in ss$.$

What is the wave speed?

Express your answer with the appropriate units.

What is the frequency?

Express your answer with the appropriate units.

What is the wave number?

Express your answer with the appropriate units.

At t$=0\mathrm{.}56$st$=0\mathrm{.}56$s$,$ what is the displacement of the string at x$=9\mathrm{.}1$mx$=9\mathrm{.}1$m$?$

Express your answer with the appropriate units.