## 19.1 Plan

So how do you do it?

Here is the idea. We create a spreadsheet, in one column
of which we start with the lower limit of integration and increase values
of the argument by
some amount, d, per row. This can be arranged by one or two entries and copying
down. You can call this the argument column.

In the next column, we evaluate
the integrand at each argument. This can be done by evaluating it at the
first entry, and copying down. This can be
called the value column for your integrand.

In the final row we sum the entries
in the previous column, each multiplied by d, This again requires one entry
and copying down. And that is essentially
it. This is the integral column. Its entry is the integral from the beginning
point to the next entry in the argument column, using the "left hand rule".

**Come
again?**

Before fleshing this out in detail, we will digress to discuss,"rules" to
use for the numerical integration.