Example Find the gradient of $\phi$．

$$\phi = x^2 z + e^{y/x}$$

Answer $\phi = x^2 z + e^{y/x}$. Then

$$\nabla \phi = \frac{\partial \phi}{\partial x}\boldsymbol{i} + \f... ...x^2}))\boldsymbol{i} + (e^{y/x}(\frac{1}{x}))\boldsymbol{j} + x^2\boldsymbol{k}$$