(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

(d) Sketch the level curve, the
unit normal vector, and the tangent line in the xy-plane.

f(x, y) = 9x - 4y c = 65, P(3, 2)