Problem $2(20$ points$)($a$)$ An idealized incompressible flow has the proposed three$-$dimensional velocity distribution V $=4$xy$?+/)$j $-$ zy$?$k$.$ Find the appropriate form of the functionfy$)$ that satisfies the continuity relation.$($b$)$ An idealized velocity field is given by the formula V $=4$xi $-2$tyj $+4$xzk$.$ Find the expression for the acceleration vector at the point $($x$,$ y$,$ z$)=(-1,1,0).$