Chapter 9, Problem 92P

The first viscous terms in $\theta$ -comonent of the Navier-Stokes eqation (Eq.9-62c) are $\mu \left[\frac{1}{r}\frac{\partial }{\partial r}\left(r\frac{\partial u_{\theta }}{\partial r}\right)-\frac{{\partial }_g}{r^2}\right]$ . Expand this expression as far as possible using the product rule, yielding three terms. Now combine all there into one term.(Hint: Use the product rule in reverse-some trail and error may be required.)