The electric potential at a point (x, y, z) is given by :V=−x2y−xz3+4The electric field E→ at that point is :

V=−x2y−xz3+4Ex=−∂V∂x=−∂−x2y−xz3+4∂x=+2xy+z3Ey=−∂V∂y=−∂−x2y−xz3+4∂y=+x2Ez=−∂V∂z=−∂−x2y−xz3+4∂z=+3xz2so=E→=Exi^+Eyj^+Ezk^