Two sinusoidal waves are described by the equations
$$y_{1}=(5.00 \mathrm{~m}) \sin [\pi(4.00 x-1200 t)]$$
and
$$y_{2}=(5.00 \mathrm{~m}) \sin [\pi(4.00 x-1200 t-0.250)]$$
where $x, y_{1}$, and $y_{2}$ are in meters and $t$ is in seconds.
(a) What is the amplitude of the resultant wave?
(b) What is the frequency of the resultant wave?