The Superposition of Two Waves $y_{1}=\left(2 \times 10^{-8} \mathrm{~m}\right) \sin \left[\pi\left(\frac{x}{2 \mathrm{~m}}-\frac{170}{\mathrm{~s}} t\right)\right]$

Multiple Choice

The superposition of two waves $y_{1}=\left(2 \times 10^{-8} \mathrm{~m}\right) \sin \left[\pi\left(\frac{x}{2 \mathrm{~m}}-\frac{170}{\mathrm{~s}} t\right) \right]$ and $y_{2}=\left(2 \times 10^{-8} \mathrm{~m}\right) \sin \left[\pi\left(\frac{x}{2 \mathrm{~m}}-\frac{170}{\mathrm{~s}} t-\frac{1}{2}\right) \right]$ , results in a wave with a frequency of:

A) 85 Hz.
B) 170 Hz.
C) 85 $\pi$ Hz.
D) 340 Hz.
E) 170 $\pi$ Hz.