> I've had many an argument with my father over this. He
> insists on using
> the binomial expansion. I prefer the Newton iteration, which
> converges
> very quickly
>
> [ To find sqrt(A)
>
> Set X(0) = A/2 (or some other suitable initial guess)
> Repeat
> X(N+1) = ( (A/X(N)) + X(N) ) / 2
> Unti X(N) and X(N+1) are sufficiently close
> Return X(N+1)
>
> ]
There's also a method I learnt long ago
that is laid out in the same way as
a long division. I've forgotten it
because it seemed moderately pointless!
I've forgotten it so thoroughly thatI've
even forgotten whether it had a name or not.
I expect that there may well be a similar
method for the cube root.
If push came to shove (i.e. no calculator,
no computer, no slide rule, no log tables)
I'd go for Newton Raphson too. I cannot
remember that one either, but I can
remember that on previous occasions when
I've needed it I've been able to regenerate it
from first principles :-)
Antonio
--
---------------
Antonio Carlini arcarlini_at_iee.org
Received on Wed Jun 23 2004 - 17:42:14 BST