(a) Find the gradient of the function at P (b) Find a unit normal vector to the level curve (x, y) = c at P

(a) Find the gradient of the function at P

(b) Find a unit normal vector to the level curve ƒ(x, y) = c at P

(c) Find the tangent line to the level curve ƒ(x, y) = c at P, and (d) sketch the level curve, the unit normal vector, and the tangent line in the xy-plane.

f(x, y) = x - y c = 3, P(4, -1)