$aP=(x{y}^2+5z+3t^2)$ Pascal and velocity field $is$ vec$(v)=$xyhat$()+$

zhat$()+7$that$(k).$ Find the rate $of$ the change $of$ the pressure $of$ the particle $(\frac{DP}{Dt})at$ a position $of(1,-3,2)$

and time $at3$ seconds?

$bu=ax-by$ where a and $b$ are constants. Find $v$

component $as$ a function $ofx$ and $y.$