This a method mainly for finding volume
s of irregular solids
First off, we define our coordinate system.
The positive X-axis is coming out of your screen towards you,
the positive Y-axis heading off to your right,
and the Z-axis is pointing straight up.
Let's suppose we have some kind of solid body, say a peanut of height h.
We define A(x) to be it's cross-sectional area at a height
x (Assuming the object is sitting on the XY-plane).
The very simply, the volume of the afore mentioned peanut is:
volume= | A(x) dx
whose approximating Reimann sum is:
Note: Braces indicate a subscript