- #1
mXSCNT
- 315
- 1
Suppose that you have a set of real variables {x1,x2,...,xn}. If x1 = f(x2,x3,...,xn) then this represents a constraint on all the variables. In this case, it's possible to find dx1/dxi as long as f is differentiable. But not all possible constraints among the xj are of this form. How might one extend the concept of derivative to the case when the constraint on all the variables is not necessarily that one variable is a function of the others?