If \displaystyle\mathbf{v}=3x^{2}y\mathbf{i}+2x y z\mathbf{j}-3x^{4}y^{2}\mathbf{k}, find {\frac{\partial{\bf v}}{\partial x}},\,{\frac{\partial{\bf v}}{\partial y}},\,{\frac{\partial{\bf v}}{\partial z}}. Further, find \frac{\partial^{2}\mathbf{v}}{\partial\mathbf{x^{2}}} and {\frac{\partial^{2}\mathbf{v}}{\partial x \partial z}}.
We find
{\frac{\partial{\bf{v}}}{\partial x}}=6x{y}\mathbf{i}+2y z\mathbf{j}-12x^{3}y^{2}\mathbf{k}
{\frac{\partial{\bf{v}}}{\partial y}}=3x^{2}\mathbf{i}+2x z\mathbf{j}-6x^{4}y\mathbf{k}
{\frac{\partial\mathbf{v}}{\partial z}}=2xy\mathbf{j}
{\frac{\partial^{2}\mathbf{v}}{\partial x^{2}}}=6y\mathbf{i}-36x^{2}y^{2}\mathbf{k}
{\frac{\partial^{2}\mathbf{v}}{\partial x\partial z}}=2y\mathbf{j}