Chapter 7.2, Problem 20P

In Problems 18 to 20, find the amplitude, period, frequency, wave velocity, and wavelength of the given wave. By computer, plot on the same axes, $y$ as a function of $x$ for the given values of t, and label each graph with its value of t. Similarly, plot on the same axes, $y$ as a function of $t$ for the given values of $x$, and label each curve with its value of $x$.

$y=3\sin \pi \left(x-\frac{1}{2}t\right);t=0,1,2,3;x=0,\frac{1}{2},1,\frac{3}{2},2$.