$\text { at } x=\frac{2 A}{3}$
$v=\omega \sqrt{A^2-\left(\frac{2 A}{3}\right)^2}=\frac{\sqrt{5} A \omega}{3}$
New amplitude $=\mathrm{A}^{\prime}$
$\mathrm{v}^{\prime}=3 \mathrm{v}=\sqrt{5} \mathrm{~A} \omega=\omega \sqrt{\left(\mathrm{A}^{\prime}\right)^2-\left(\frac{2 \mathrm{~A}}{3}\right)^2}$
$\mathrm{A}^{\prime}=\frac{7 \mathrm{~A}}{3}$

$y_{2}=5(\sin 3 \pi t+\sqrt{3} \cos 3 \pi t)$
Ratio of amplitude of ${y}_{1}$ to ${y}_{2}={x}: 1$. The value of ${x}$ is ...... .