# Math Help - Theory Problem

1. ## Theory Problem

How can you show that $\int\int\frac{\vartheta^{2}F(x,y)}{\vartheta x \vartheta y}$ $dx dy$ over the rectangle $x_{0}\le x \le x_{1}$, $y_{0}\le y \le y_{1}$, is $F(x_{1},y_{1})-F(x_{0},y_{1})-$ $F(x_{1},y_{0})+F(x_{0},y_{0})$.

2. See attachment