Example M3.

  1. Sketch the region defined by the following system of simultaneous inequalities: $$ x\ge0,\ y\ge0,\ {1\over2}\sqrt{x^2+y^2}\le z\le 3. $$
  2. Suppose the given region contains a charge density $\rho_V$ whose values depend only on distance from the $z$-axis, i.e., $\rho_V=\rho_V(\sqrt{x^2+y^2})$ is a function of just one variable. Express the total charge in the region as a single definite integral.