Math Help - Rate of Change as moving toward a point

Find the rate of change of f(x,y,z) = ln(x+yz^2)-sin(y+z)+xe^y at the point (0,1,-1) as you move toward the point (4,1,2)

Originally Posted by crwhd4

Find the rate of change of f(x,y,z) = ln(x+yz^2)-sin(y+z)+xe^y at the point (0,1,-1) as you move toward the point (4,1,2)

you want the directional derivative here.

first, find the vector from (0,1,-1) to (4,1,2).

then find the unit vector in that direction

then use the formula:

where is the gradient vector of (at the point (0,1,-1)), is the dot product and is the unit vector i asked you to find.