Suppose f$($x$,$y$)=$x$/$y$,$ P$=(-4,1)$ and v$=-1$i$-2$j $.$ A$.$ Find the gradient of f$.$ Note: Your answers should be expressions of x and y; e$.$g$."3$x $-4$y$"$

B$.$ Find the gradient of f at the point P$.$

C$.$ Find the directional derivative of f at P in the direction of $.$

D$.$ Find the maximum rate of change of f at P$.$

E$.$ Find the $($unit$)$ direction vector in which the maximum rate of change occurs at P$.$