Multivariable calculus - Wikipedia
https://en.wikipedia.org/wiki/Multivariable_calculusTechniques of multivariable calculus are used to study many objects of interest in the material world. In particular, Multivariable calculus can be applied to analyze deterministic systems that have multiple degrees of freedom. Functions with independent variablescorresponding to each of the degrees of freedom are often used to model these systems, and multivariable calculus provides tools for ch…