Overview
The multiple riemann integral gives meaning to integrals such as
{% {\displaystyle \int } {\displaystyle \int } f(x,y) dx dy %}
These integrals can be easily understood if one looks at the inner integral and defines the following function
{% g(y) = {\displaystyle \int } f(x,y) dx %}
Then, we can defined the double integral to be
{% {\displaystyle \int } g(y) dy %}