Over a certain region of space the electric potential is giv
     Over a certain region of space, the electric potential is given by V - 5x -  3x^y + 2yz^2. Find the expressions for the x, y, and z components of the electric  field over this region. What is the magnitude of the field at the point P, which  has coordinates (in meters) (1,0, - 2)?
  Solution
Ex = - dV/dx = 5 - 6xy = 5 - 6 (1) (0) = - 5
Ey = - dV/dy = 0 - 6x2 + 2z2 = - 6 (1)2 + 2 (-2)2 = - 2
Ez = - dV/dz = 4yz = 4 (0) (-2) = 0
magnitude of electric field = E = sqrt(Ex2 + Ey2 + Ez2) = sqrt((-5)2 + (-2)2 + (0)2) = 5.4
