## The error term is 1, not a rigorous bound.

## Previous formula works fine if

*V*is simple.## What if we want to integrate a function

*g*over a region*W*that is*not*easy to sample randomly?## Solution: find a simple volume

*V*that*encloses**W*and define a new function*f*(**x**),**x***V*such that:*f*(**x**) =*g*(**x**) for all**x***W**f*(**x**) = 0 otherwise