Waves

The path difference between two waves, represented by \(\mathrm{y}_1=\mathrm{a}_1 \sin \left(\omega \mathrm{t}-\frac{2 \pi \mathrm{x}}{\lambda}\right)\) and \(y_2=a_2 \cos \left(\omega t-\frac{2 \pi x}{\lambda}+\phi\right)\) is