Use a CAS to perform the following steps for each of the functions.
a. Plot the surface over the given rectangle.
b. Plot several level curves in the rectangle.
c. Plot the level curve of $f$ through the given point.
$$\begin{array}{l} f(x, y)=\sin (x+2 \cos y), \quad-2 \pi \leq x \leq 2 \pi, \quad -2 \pi \leq y \leq 2 \pi, \quad P(\pi, \pi) \end{array}$$