The temperature in a region of interest is determined to be given by the function T = x2 + xy + yz. At the point (2, 1, 4), answer the following questions.
1. What is the unit vector that points in the direction of maximum change of temperature?
2. What is the value of the derivative of the temperature in the x direction?
3. What is the value of the derivative of the temperature in the direction of the vector i - 2j + 2k?