Let $f(x,y)=\frac{1}{2}{x}^2{y}^2-y.$

$afat$ the point $(1,2).$

$bfat(1,2)in$ the direction $of$ vec$(v)=-3$vec$(i)+4$vec$(j).$

$cfat(1,2)$ and the rate $of$ change

$in$ that direction.