## Re: SR Prob : Solve for x

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• ... / o o oo o o o o oo o o oo o ooooo / / o o oo o oooo o oo oo o / / o o ooo
Message 1 of 6 , Dec 1 9:37 AM
gsflom1 wrote:
> Solve to SR precision :
>
> log (base 10) x = (x ^ 2) - 2 .
>

---------------------------------------------------------------
/ o o oo o o o o oo o o oo o ooooo /
/ o o oo o oooo o oo oo o /
/ o o ooo o o ooooo oo ooooo o /
/............................................................../
< o o oo o o oo ooooo o oo <
\ o o o o o o o o \
\ o o o o o \
\ oooo oo ooooooo oooooooo oooooooooo \
\ooooooooooo o oo o oo oo ooo ooooooooooooooo\
---------------------------------------------------------------

Graph the two functions and identify approximate solutions. There are
two solutions: x ~= .01 and x ~= 1.5.

Set cursor to 1.5 on D read L = 0.176, A = 2.25. A is too big so slide
cursor to left until L coincides to fractional part of A. This gets you
to L = .168 A = 2.17 thus D = 1.472.

Observe that .01^2 - 2 is so close to log10(.01) there is no point in
using a slide rule.

Numeric solutions are: 1.472424171, 0.0100230391.

--Mark
• ... The Yahoo Groups mail reader sure mangled that! Let s try again... ... Extra credit for decoding the tape. --Mark [Non-text portions of this message have
Message 2 of 6 , Dec 1 2:13 PM
--- In sliderule@yahoogroups.com, Mark Armbrust <mark.armbrust@...>
wrote:
>
> [some well mangled ASCII art]

The Yahoo Groups mail reader sure mangled that! Let's try again...

| ---------------------------------------------------------------
| / o o oo o o o o oo o o oo o ooooo /
| / o o oo o oooo o oo oo o /
| / o o ooo o o ooooo oo ooooo o /
| /............................................................../
| < o o oo o o oo ooooo o oo <
| \ o o o o o o o o \
| \ o o o o o \
| \ oooo oo ooooooo oooooooo oooooooooo \
| \ooooooooooo o oo o oo oo ooo ooooooooooooooo\
| ---------------------------------------------------------------

Extra credit for decoding the tape.

--Mark

[Non-text portions of this message have been removed]
• Mark, Nice ascii art! Did you write a program or do this manually? HERE IS ANOTHER OBSOLETE TECHNOLOGY! I decoded manually but halfway through was
Message 3 of 6 , Dec 1 5:27 PM
Mark,

Nice ascii art! Did you write a program or do this manually?

HERE IS ANOTHER OBSOLETE TECHNOLOGY!<cr>

I decoded manually but halfway through was thinking a program would have
been well worth the effort. :-)

Mike

> --- In sliderule@yahoogroups.com, Mark Armbrust <mark.armbrust@...>
> wrote:
>> [some well mangled ASCII art]
>
> The Yahoo Groups mail reader sure mangled that! Let's try again...
>
> | ---------------------------------------------------------------
> | / o o oo o o o o oo o o oo o ooooo /
> | / o o oo o oooo o oo oo o /
> | / o o ooo o o ooooo oo ooooo o /
> | /............................................................../
> | < o o oo o o oo ooooo o oo <
> | \ o o o o o o o o \
> | \ o o o o o \
> | \ oooo oo ooooooo oooooooo oooooooooo \
> | \ooooooooooo o oo o oo oo ooo ooooooooooooooo\
> | ---------------------------------------------------------------
>
> Extra credit for decoding the tape.
>
> --Mark
• ... I wrote a program to do this a long time ago (timestamp on the source is 5/9/97) and a companion program that does punch cards. I just remembered them
Message 4 of 6 , Dec 1 9:18 PM
Mike Markowski wrote:
> Mark,
>
> Nice ascii art! Did you write a program or do this manually?
>
> HERE IS ANOTHER OBSOLETE TECHNOLOGY!<cr>
>
> I decoded manually but halfway through was thinking a program would have
> been well worth the effort. :-)
>
> Mike
>

I wrote a program to do this a long time ago (timestamp on the source is
5/9/97) and a companion program that does punch cards. I just
remembered them during the obsolete technology thread.

--Mark
• Very good ! Gary Flom ... From: Mark Armbrust To: sliderule@yahoogroups.com Sent: Saturday, December 01, 2007 12:37 PM Subject: Re: SR Prob : Solve for x ... /
Message 5 of 6 , Dec 1 9:48 PM
Very good !

Gary Flom

----- Original Message -----
From: Mark Armbrust
To: sliderule@yahoogroups.com
Sent: Saturday, December 01, 2007 12:37 PM
Subject: Re: SR Prob : Solve for x

gsflom1 wrote:
> Solve to SR precision :
>
> log (base 10) x = (x ^ 2) - 2 .
>

----------------------------------------------------------
/ o o oo o o o o oo o o oo o ooooo /
/ o o oo o oooo o oo oo o /
/ o o ooo o o ooooo oo ooooo o /
/............................................................../
< o o oo o o oo ooooo o oo <
\ o o o o o o o o \
\ o o o o o \
\ oooo oo ooooooo oooooooo oooooooooo \
\ooooooooooo o oo o oo oo ooo ooooooooooooooo\
----------------------------------------------------------

Graph the two functions and identify approximate solutions. There are
two solutions: x ~= .01 and x ~= 1.5.

Set cursor to 1.5 on D read L = 0.176, A = 2.25. A is too big so slide
cursor to left until L coincides to fractional part of A. This gets you
to L = .168 A = 2.17 thus D = 1.472.

Observe that .01^2 - 2 is so close to log10(.01) there is no point in
using a slide rule.

Numeric solutions are: 1.472424171, 0.0100230391.

--Mark

[Non-text portions of this message have been removed]
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