A traveling wave has displacement given by \(y(x, t)=\) \((2.0 \mathrm{~cm}) \times \cos (2 \pi x-4 \pi t)\), where \(x\) is measured in \(\mathrm{cm}\) and \(t\) in \(\mathrm{s}\).

a. Draw a snapshot graph of this wave at \(t=0 \mathrm{~s}\).

b. On the same set of axes, use a dotted line to show the snapshot graph of the wave at \(t=1 / 8 \mathrm{~s}\).

c. What is the speed of the wave?