"Gilligan" wrote in message
. ..

"Edgar" wrote in message
...


Rule of Thumb does not normally call for a knowledge of calculus...



Here are some rules of thumb for the applications of integrals in
calculus:

http://www.math.hawaii.edu/~lee/calculus/Integrals.html

Is this abnormal?

No, I would say it is normal. His 'rules of thumb' are directed at people
who have not yet, or do not need, to learn the theories in their entirety,
and he admits that they do contain inaccuracies.
That is exactly what a 'rule of thumb' is- a shortcut for everyday use for
those who do not wish, or are unable, to get too deeply involved in the
basic theorems.