A) Find the directional derivative of the function at the givenpoint in the direction of vector v. f(x, y) = 5 + 6x√y, (5, 4), v =<8, -6>
Duf(5, 4) =
B) Find the directional derivative,Duf, of the function at the givenpoint in the direction of vector v.
f(x, y)=ln(x2+y2), (4, 5),v = <-5, 4>
Duf(4, 5) =
C) Find the maximum rate of change of f at the givenpoint and the direction in which it occurs.
f(x, y) =3 y2/x,(2, 4)
direction of maximum rate of change (in unit vector) = <   ,  >
maximum rate of change =
D) Find the directional derivative of f at the givenpoint in the direction indicated by the angle θ.
f(x, y) = 2x sin(xy), (5,0), θ = π/4
Duf =
