4.A] Find the directional derivative of \phi = x^2yz + 4xz^2 at (1, -2, -1) in the direction of 2\hat{i} - \hat{j} - 2\hat{k}
Answer:

4.A] Find the directional derivative of \phi = x^2yz + 4xz^2 at (1, -2, -1) in the direction of 2\hat{i} - \hat{j} - 2\hat{k}
Answer: