Thread: uffda.
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Jeff Morris
 
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Default uffda.

Well, I wouldn't say its so easy that jaxie can follow, but there are all sorts
of techniques that have been developed over the years. Computers don't use
"magic" to calculate complex functions, there are often just programmed to
follow algorithms developed many years ago by people like Newton. Jaxie forgets
that this is what I did for a living.

To compute a 4th root, using Newton's method:

Assume you want to compute x = a^(1/4)
Make a guess at the answer, call it x1. Then compute the next guess, x2, as
follows:
x2 = x1 - (x1^4 - a)/(4 * x1^3)
iterate again as
x3 = x2 - (x2^4 - a)/(4 * x2^3)

When the results get sufficiently close, you have an answer. Often only 3 or 4
iterations are needed. Similar techniques can be used to calculate the roots of
polynomials.

I used the square root version of this a number of times. In the days before
"Floating Point Units" in computers considerable time savings (a factor of 10 or
more) could be had by adjusting the algorithms to match the input data and
desired accuracy.




"JAXAshby" wrote in message
...
wanna show us how?

]okay group, watch now how jeffies blathers on for days telling us that what
with his degree in physics and all that he can do it easily. if I say he can
not he will get all snippy. he couldn't tell us how RDF worked how is he

going
to tell us how to do 4th roots with pencil and paper.]

jeffies? do note the word algebraicly was there. in other words, SWAGing is
not the answer.

What's so hard about doing 4th roots with pencil and paper?



"JAXAshby" wrote in message
...
bull. there is no intuitive way to calculate the product of those numbers

in
that way, any more than you can calc a 4th root of a number algabraicly

with a
pencil and paper.