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Re: Solve / Reduce isolating results.

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  Re: Solve / Reduce isolating results. leni536 <leni536@gmail.com> - 2011-04-30 09:51 +0000

#1918 — Re: Solve / Reduce isolating results.

On =E1pr. 29, 13:35, "Lea Rebanks" <lreba...@netvigator.com> wrote:
> Dear All,
>
> Given the enclosed code - see below.
> Please could someone help me setup the code to Solve / Reduce for these 2
> missing values only required
>
>   {SQ1 -> 5292,
>     XX -> 0.25}
>
> (I don't want multiple results.) I want positive numbers & NOT Complex..
>
> Many thanks for your help & attention, really appreciated. Please see below.
>
> Best regards,
> Lea...
> ...................................................................
>
> Clear[SQ1]
> Clear[XX]
> Solve[{(1/6)*((SQ1*196)*2)^3 -
>          (1/6)*((((2.75 + XX)*((3.75 + XX)*21^2))*100)*2)^3 ==
>        1.2902698935932682*^18, (1/6)*((SQ1*100)*2)^3 -
>          (1/6)*((((2.75 + XX)*((3.75 + XX)*21^2))*36)*2)^3 ==
>        1.883856772422697*^17}, {SQ1, XX}]

Clear[SQ1]
Clear[XX]
positiveRealQ[x_] := If[Im[x] == 0, x > 0, False];
Select[{SQ1, XX} /.
  Solve[{(1/6)*((SQ1*196)*2)^3 - (1/
         6)*((((2.75 + XX)*((3.75 + XX)*21^2))*100)*2)^3 ==
     1.2902698935932682*^18, (1/6)*((SQ1*100)*2)^3 - (1/
         6)*((((2.75 + XX)*((3.75 + XX)*21^2))*36)*2)^3 ==
     1.883856772422697*^17}, {SQ1, XX}],
 And @@ (positiveRealQ /@ #) &
 ]

Regards,
Lenard

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