7. Consider a vacuum region, 0 < x < a, bounded by two grounded perfectly
conducting walls at x = 0 and x = a. A surface charge density $\rho_0 \sin(\frac{3\pi}{a}x)$ is
placed on y = 0, 0 < x < a.
a) What is the electrostatic potential in the region 0 < x < a?(10%)
b) What is the total charge (per unit length in z) on the surface of the conductor
at x = 0? (10%)