4. Evaluate the first partial derivatives of the function \( h(x, y, z)=z \sin \left(x^{2} y\right) \) at the point \( A\left(1, \frac{\pi}{2}, 2\right) \). 5. Find \( \frac{\partial z}{\partial y} \) and \( \frac{\partialxz}{\partial x} \) the xe
y
+ye
z
+sin(yz)=2ln(xz).