Question

Suppose f ( x, y ) = 1 x2 + 2 xy − 1 y2, P = ( 1, −1), and u = ( [(−7)/25],[24/25] ).

A. Compute the gradient of f.
∇f = ??? I + ??? J
Note: Your answers should be expressions of x and y; e.g. "3x - 4y"

B. Evaluate the gradient at the point P.
( ∇f ) ( 1, −1 ) = ??? I + ??? J
Note: Your answers should be numbers

C. Compute the directional derivative of f at P in the direction u .
( Du f ) ( P ) = ???
Note: Your answer should be a number