Directional derivatives and slope
10:32
Why the gradient is the direction of steepest ascent
12:01
Directional Derivatives | What's the slope in any direction?
6:54
Partial derivatives and graphs
12:45
Vector valued function derivative example | Multivariable Calculus | Khan Academy
7:58
Formal definition of partial derivatives
7:14
Directional derivative
14:51
Geometric Meaning of the Gradient Vector
9:48