Final answer:
To find the rate of change of temperature at point P (4, -1, 5) in the direction towards point (6, -3, 6), first calculate the gradient vector of the temperature function. Then, find the unit vector in the direction towards the second point and calculate the dot product between the gradient vector and the unit direction vector.
Step-by-step explanation:
To find the rate of change of temperature at point P (4, -1, 5) in the direction towards point (6, -3, 6), we can first find the gradient vector of the temperature function T(x, y, z) = 400e⁻ˣ² - 5y² - 9z². The gradient vector represents the direction of the steepest increase of the function.
Next, we can calculate the direction vector between the two points and normalize it to obtain the unit vector in the direction towards the second point. Finally, we can find the dot product between the gradient vector and the unit direction vector to calculate the rate of change of temperature.