Use MATLAB for plotting 3. D data for the following functions:

(a) $z=\cos x \cos y e^{-\sqrt{\frac{x^{2}+y^{2}}{5}}}|x| \leq 7,|y| \leq 7$

(b) Discrete data plots with stems

$x=t, \quad y=t \cos (t)$

$z=e t / 5-2 \quad 0 \leq x \leq 5 \pi$

(c) An ellipsoid of radii $r x=1, r y=2.5$ and $r z=0.7$ centered at the origin(d) A cylinder generated by

\[\begin{array}{ll}r=\sin (5 \pi z)+3 & 0 \leq z \leq 1 \\& 0 \leq \theta \leq 2 \pi\end{array}\]