Use Stokes' theorem to compute the circulation $o{\displaystyle \underset{C}{\overset{\phantom{}}{}}}$vec$(F)*dvec(r)$ where vec$(F)=($:$3xyz,4y^{2}z,9yz$:$)$ and $C$ is the boundary of the portion of the plane $2x+3y+z=6$ in the first octant. Here $C$ is positively oriented with respect to the plane whose orientation is upward.