Science:Math Exam Resources/Courses/MATH200/December 2013/Question 01 (c)/Statement

Suppose that $u=x^2+yz,x=\rho r\cos (\theta ),y=\rho r\sin (\theta )$ and $z=\rho r$. Find $\frac{\partial u}{\partial r}$ at the point $({\rho }_0,r_0,{\theta }_0)=(2,3,\pi /2)$.