$\left[\frac{0.6 \times 400}{ v }+1\right] \frac{ v }{0.6}=450$
$= v =30$
$\sqrt{\frac{ T }{\mu}}=30$
$\frac{2700}{\mu}=900=\mu=3$

${y_1} = {10^{ - 6}}\sin [100\,t + (x/50) + 0.5]m$
${y_2} = {10^{ - 6}}\cos \,[100\,t + (x/50)]m$
where $ x$ is expressed in metres and $t$ is expressed in seconds, is approximately .... $ rad$