Answer
$y=(0.11m)cos(\frac{2\pi}{2.6m}x-\frac{2\pi}{0.18s})t$
Work Step by Step
As $T=\frac{\lambda}{v}$
$T=\frac{2.6}{14.3}$
The required expression can be written as
$y=Acos(\frac{2\pi}{\lambda}x-\frac{2\pi}{T}t)$
We plug in the known values to obtain:
$y=(0.11m)cos(\frac{2\pi}{2.6m}x-\frac{2\pi}{0.18s})t$
