# Question #ca0cb

If $f \left(x , y , z\right) = x \sin \left(y + 2 z\right) + x {y}^{2}$, $\frac{\partial f}{\partial x} {|}_{y , z} = \sin \left(y + 2 z\right) + {y}^{2}$
Assuming that the function is of three variable $x , y , z$ then to partially differentiate wrt one of the three just treat the other two as constants.