Re: Checking simplified algebraic expressions (the -3 test)

Arturo Magidin <magidin@[EMAIL PROTECTED]
> writes:

>
> In other words: you encourage them to check a universal proposition by
> making a single test case?
>

Well, that's not necessarily that bad. After all, doing any maths, say
topology, it really helps to "draw a picture" and check that what
you're trying to prove or the argument you have used does at least
hold somewhere.

It's a good check against idiotic mistakes. I definitely don't confuse
it with a proof, but since (theorem true) => (theorem works in a given
situation), you can definitely use it as a sanity check.

Anyway, I contend that this is just the same as the approach
michalchik@[EMAIL PROTECTED]
 is using (on numbers). And indeed I do it myself -
it's pretty darn unlikely that if you got it wrong, your two formulas
will be equal on say 2,3,-3.

No, it's not a proof. But it is a good check. How else do you suggest
checking this sort of thing (no CAS!)? Doing your "proof" again will
of course not work if you misunderstood something - you'll of course
get the same answer again.


Rupert