LEFT[ \mathbf{i}\FRAC{\PARTIAL V}{\partial x}+\mathbf{j}\frac{\partial V}{\partial y}+\mathbf{K}\frac{\partial V}{\partial z} \RIGHT]\] So, \[\mathbf{E}=-\mathbf{i}\frac{\partial V}{\partial x}=-\mathbf{i}\frac{\partial }{\partial z}(4{{x}^{2}})\] \[=-8x\,\mathbf{i}\,\text{V}\,{{\text{m}}^{-1}}\] \[{{\mathbf{E}}_{(1,0,2)}}=-8\,\mathbf{i}\,\text{V}{{\text{m}}^{-1}}\]