Directional derivatives and gradient vectors:

Translation:

The electrical potential V in the point (x,y,z) is given by V= -x^2-8y^2+4z^2,

determine the following:

a) the reason of the change of V in P(2,-4,3) in the direction of P to the origin.

DuV(P)=

b) What is the reason of the maximum growth:

Dumax V(P)=

c) What is the direction in which it occurs?

unitarium vector= ____ i+ _____j+ ______k