Directional Derivatives

Question 1

What is the directional derivative?

Answer 1

DD of f at point a,b in the direction of the unit vector u = (x0, y0) is given by the limit in notes.

Question 1

What is the relationship between Directional Derivative and Partial Derivative?

Answer 1

If u = 1, 0
then directional derivative is equal to partial derivative of x.
same for y.