**Find the directional derivative of f(x,y,z)=z^(3)-x^(2)y at the point (5,5,2) in the direction of the vector v=<1,-5,-3>**

**Answer:**

**Find the directional derivative of f(x,y,z)=z^(3)-x^(2)y at the point (5,5,2) in the direction of the vector v=<1,-5,-3>**

**Answer:**