Greens' Theorem (1825)

Theorem: Under suitable conditions of continuity and the existence of various partial derivatives, the double integral for the area of a closed region can be re-stated as a line integral around the region. Green's Theorem is derived from a more general theorem in multivariable calculus known as Stoke's Theorem. Essentially this mean that it is possible, in some instances, to determine the value of an integral across a closed region by considering only the boundary, and disregarding the interior altogether.

Author: George Green first established his famous theorem around 1825.

Importance: Green's theorem allows for some difficult integrals in multivariable calculus to be re-expressed in another form. Occasionally this new form will be solvable, whereas the original integral was not.