If you want to evaluate a particular integral, you can do it with amazing
ease on a spreadsheet. It should take no more than ten minutes to set up an
integrating spreadsheet, and once you have one, you can apply it to a new integrand
in under a minute. All you need do is enter your integrand once, copy it into
a rectangle, and enter your limits of integration.
Since it is so convenient to do this, you would be wise to check any integral you evaluate numerically. If your formal answer and the numerical answer agree, you are definitely right, so long as you got the question you are answering right.
19.2 "Rules" for Integrating
19.3 Why Do these Rules Work?
19.4 Numerical Integration in Detail
19.5 Where do we go from here?