Final answer:
The Derivative Calculator is used to find local minimum and maximum values of functions with two variables.
Step-by-step explanation:
The calculator used for finding local minimum and maximum values of functions with two variables is the Derivative Calculator. This calculator can compute partial derivatives with respect to both variables and determine critical points where the derivative is zero or undefined. By analyzing these critical points and the behavior of the function around them, you can identify local minimum and maximum values.