Find the directional derivative of f(x,y,z) = 4xy + z^2 at the point (2,2,-4) in the direction of a vector making an angle of π/3 with ∇f(2,2,-4).
The concentration of salt in a fluid at (x,y,z) is given by F(x,y,z) = 2x^2 + 2y^4 + 4x^2z^2 mg/cm^3. You are at the point (-1,-1,-1).
(a) In which direction should you move if you want the concentration to increase the fastest?
direction:
(Give your answer as a vector.)
(b) You start to move in the direction you found in part (a) at a speed of 33 cm/sec. How fast is the concentration changing?
rate of change =
Consider the function f(x,y) = -4x^2 - 2y^2.
Find the directional derivative of f at the point (-3,-4) in the direction given by the angle θ = π/3.
Find the unit vector which describes the direction in which f is increasing most rapidly at (-3,-4).