1. If we have u = f(x,y,z) where x = x(s,t), y = y(s,t), and z = z(s,t), write out the appropriate Chain Rule for .
 
 

2. If g(x,y) = cos x + sin y, in which direction is the directional derivative greatest at the point (, /6), and what is the slope in that direction?
 
 

3. Find the directional derivative of h(x,y) = ln(x - y) at the point (2, 1) in the direction of the vector <-3,4>.