A transverse wave on a string is given by $(x,t)=(0\mathrm{.}2m{)}^{**}cos(6\mathrm{.}28m^{-1**}x-1\mathrm{.}57s^{-1}t).$ Find the amplitude and wavelength of the wave.

a$)$ Amplitude $1$ m $,$ wavelength $0\mathrm{.}2$ m

b$)$ Amplitude $0\mathrm{.}2$ m $,$ wavelength $1$ m

c$)$ Amplitude $0\mathrm{.}2$ m $,$ wavelength $6\mathrm{.}28$ m

d$)$ none of these.

For the problem $(12)$ above, Find the period and speed of the wave.

a$)$ Period $=4s,$ speed $=0\mathrm{.}25\frac{m}{s}$

b$)$ Period $=0\mathrm{.}25s,$ speed $=4\frac{m}{s}$

c$)$ Period $=4s,$ speed $=4\frac{m}{s}$

d$)$ none of these.