$y_1=A \sin \left(k x-\omega t+\frac{\pi}{6}\right), \quad y_2=A \sin \left(k x-\omega t-\frac{\pi}{6}\right)$
The equation of resultant wave is
$y=y_1+y_2$
or $y=A \sin \left(k x-\omega t+\frac{\pi}{6}\right)+A \sin \left(k x-\omega t-\frac{\pi}{6}\right)$
or $y=2 A \sin (k x-\omega t) \cdot \cos \left(\frac{\left(\frac{\pi}{6}+\frac{\pi}{6}\right)}{2}\right)$
or $y^{\prime}=2 A \frac{\sqrt{3}}{2} \sin (k x-\omega t)$
$\therefore y^{\prime}=A \sqrt{3} \sin (k x-\omega t)$

$y_1=5 \sin 2 \pi(75 t-0.25 x)$
$y_2=10 \sin 2 \pi(150 t-0.50 x)$
The intensity ratio $\frac{I_1}{I_2}$ of the two waves is