Directional Derivatives and the Gradient Vector.

0:00 The Partial Derivatives as a Definition.

1:21 Directional Derivatives in the Direction of a Unit vector " u ".

10:15 Example; Give a Cubic Function " f ( x, y) = x^3 - 3xy +4 y^2

               a ) Find The Direction Derivative when Theta is 30 Degrees.

                b ) Find The Direction Derivative at ( 1, 2 ).

12:29 The Gradient Vector.

15:07 Example on The Gradient Vector.

16:21 Example on the Directional Derivative.

18:31 Functions of Three Variables.

25:59 Maximizing the Directional Derivative.

24:18 Example the Maximum Rate of Change and its Direction.