[taos-glug] Re: Question 1.46

  • From: Jonathan Bartlett <johnnyb@xxxxxxxxxx>
  • To: taos-glug@xxxxxxxxxxxxx
  • Date: Wed, 13 Aug 2003 10:05:56 -0700 (PDT)

It's not unusual that different guesses would get different results, but
they should all be within the specified precision.  The reason I didn't
allow the guess as a parameter is that I didn't want to clutter up the
user interface w/ impl. details (I figured that since it's impossible to
get exact answers, precision was legitamately a part of the interface, but
"guess" wasn't, because there may be a way to write these without the
guess.

Anyway, I have a feeling there's a more natural way to put together the
problem than the way I did it, but I haven't thought of it yet.

Jon

On Wed, 13 Aug 2003, Philip Ansteth wrote:

>
> Jon,
>
> I'll buy your solution.   I didn't try that exercise, nor 1.45.
>
> However, I am curious about something.   I get slightly different answers
> with different initial guesses.   Or I think that's what's going on.   Maybe
> you can explain it easily.  Here's what I did to get the following:
>
> You have 5 as an initial guess.   I thought, Why not pass that as a 
> user-definable
> parameter?   Besides, I wanted to make sure that that's what the 5 actually 
> was--although
> later I saw that you had commented to that effect.
>
> guile> (square-root 33 .001)           ; your routine as is
> 5.74456265264727
>
> Next I changed the argument list:  (define square-root (lambda (number 
> precision my-guess)
> And changed 5 to my-guess.   That yielded the same result with 5:
>
> guile> (square-root 33 .001 5)
> 5.74456265264727
>
> But when I tried other numbers I got slightly different results.
>
> guile>  (square-root 33 .001 1)
> 5.74456264846024
> guile> (square-root 33 .001 3)
> 5.74456274840839
> guile> (square-root 33 .001 -1)
> -5.74456264846024
> guile>
>
> I didn't pursue it any farther than that.
>
> I'm trying to keep moving forward.  The summer project is about to run out of 
> summer,
> with 500 pages still to go.   Today I'm going to look at electrical 
> resistance problem
> in Section 2.1.4, first to see if it looks like a worthwhile project, and 
> then maybe
> to try it.
>
> Philip
>
>


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