Use the Chain Rule to find the indicated partial derivatives.
, r = y + x cos(t), s = x + y sin(t);
when x = 2, y = 2, t = 0
Hello,
$\displaystyle \frac{\partial u}{\partial x}=\frac{\partial u}{\partial r} \cdot \frac{\partial r}{\partial x}+\frac{\partial u}{\partial s} \cdot \frac{\partial s}{\partial x}$
read this : The Multivariable Chain Rule - HMC Calculus Tutorial