(Solved):
4. Determine the gradient, divergence, curl, and Laplacian of the velocity field \( \boldsymbol{u} ...
4. Determine the gradient, divergence, curl, and Laplacian of the velocity field \( \boldsymbol{u}=\mathrm{z} \theta \boldsymbol{e}_{r}+z r \boldsymbol{e}_{\theta}+r \theta \boldsymbol{e}_{z} \) in cylindrical coordinates.