(a) Find a vector parametric equation for the part of the saddle $z = xy$ inside the cylinder $x^2 + y^2 = 9$.

$\boldsymbol{\vec{r}}(u,v) =$ for $0 \leq u \leq 3$ and $0 \leq v \leq 2\pi$.

(b) $\displaystyle \boldsymbol{\vec{r}}_u \times \boldsymbol{\vec{r}}_v =$

(c) Compute and simplify: $\displaystyle \left\| \boldsymbol{\vec{r}}_u \times \boldsymbol{\vec{r}}_v \right\| =$

(d) Set up and evaluate a double integral for the surface area of the part of the saddle inside the cylinder.

Surface area =