How much red?

How much red?

We would like our notion of amount (that we're going to call the "integral") to have the following properties:

amount()= 2 times amount()

amount() = half of amount()

amount() = 0

These would all be true if, for a uniform image of redness r,

amount() = r times area()


The notion of amount called the "integral" and defined as the limit of Riemann sums, is based on this last property, and gives sensible answers for uniform and non-uniform images:

integral() = 1

integral() = 2

integral() = 0.5

integral() = 0

integral() = 8/27 = .296...