[ExI] mersenne primes again

spike spike66 at att.net
Thu Apr 1 21:35:16 UTC 2010


> ...On Behalf Of spike
> Subject: Re: [ExI] mersenne primes again
... 
> > So what are you proposing as an alternative/replacement?
> 
> Dunno.  But I see plenty of reason for hope...spike

Nah, I can do better than that.  I do have an idea.

In engineering school, we spend four full quarters learning traditional
calculus, then another quarter of differential equations.  All that valuable
classroom time is spent learning how to do closed form solutions, integrals
and differentials.

In my 26 yr career as a rocket scientist, I used that skill only four times,
and even that understates my point.  In any big company, you don't need to
know the answer, you only need to know the cat who knows the answer.  I was
the go-to guy on math; any math question I had the reputation as the one to
see, and please do, I love all kinds of math.  But closed-form integration
and differentiation is pretty much a useless skill in itself, yet we invest
huge amounts of undergrad energy and time in it.

In the real world, if you ever get a real calculus type problem, you do the
integration digitially.  Hell, Newton realized this about 10 minutes after
he invented calculus, way back in the days before all the cool integrations
had been done.  If you look at his Principia, you will find he spent most of
his time figuring out approximation methods, because that is the really
useful skill.

An alternative to learning how to integrate closed-form functions might be
learning to really get hot with your spreadsheets, do digital approximations
of the integrals.  In fact, you could use a spreadsheet to estimate all your
differentials, and so you could work backwards and figure out the closed
form derivative from digital results.  

Recently Keith and I were fooling with a spreadsheet I wrote about 15 yrs
ago to estimate rocket booster performance taking into account aerodynamic
drag and rocket motor thrust.  That is a really good example of a real-world
problem that cannot be done effectively in closed form, because there are
too many variables changing too many ways.  

Better than spending a year on calculus would be a parallel path which
students could choose, which takes advantage of a tool we didn't have in my
misspent youth: the spreadsheet.

spike





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