In the real world physical quantities often depend on several variables. How do you determine the slope of such functions?
Partial Derivatives
In this video you'll learn how to calculate the partial derivatives of f with respect to x or y at a point (a,b) of a function f of two variables.
Chain rule
How do you calculate the derivative of a composed function of several variables? In this video you learn how to use the chain rule for functions of 2 variables, with both variables depending on another variable.
Directional Derivative
In this video you'll learn how to calculate the directional derivative of f in the direction of the unit vector u, f being a function of two variables.
Domains and maxima
A closed domain is a domain which includes its entire boundary. A continuous function on a closed and bounded domain always has a global maximum and minimum.