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Re: On Reduce

  • To: mathgroup at smc.vnet.net
  • Subject: [mg72173] Re: [mg72011] On Reduce
  • From: Virgil Stokes <vs at it.uu.se>
  • Date: Wed, 13 Dec 2006 06:42:23 -0500 (EST)
  • References: <200612081118.GAA20205@smc.vnet.net> <B874AACE-F0C2-4869-9588-5B3DDBBB8183@mimuw.edu.pl>

Andrzej Kozlowski wrote:
>
> On 8 Dec 2006, at 20:18, Virgil Stokes wrote:
>
>> I have the following small piece of Mathematica code that works fine for
>> my purposes.
>>
>>  BInv = {{  1/4, 1/4, 0},
>>               {-1/2, 1/2, 0},
>>               {  3/4, -5/4, 1}}
>>  B = Inverse[BInv]
>>  b = {4 + \[Delta], 8, 10};
>>  BInv.b // FullSimplify
>>  Reduce[{%[[1]] >= 0, %[[2]] >= 0, %[[3]] >= 0}, {\[Delta]}]
>>  % /. {\[Delta] -> b1 - 4} // FullSimplify
>>
>> which gives
>>
>> 0 <=  b1 <= 8
>>
>> which is of course correct. But, how can I use (access) the values 0 
>> and 8?
>> That is, I would like to now use these values in some expressions that
>> would follow this.
>>
>> Thanks,
>> V. Stokes
>>
>
>
> Do you mean you wan tot extract the pair {0,8} as a list? There are 
> lots of way, e.g.
>
>
> Cases[%,_?NumericQ]
>
> {0,8}
>
> Andrzej Kozlowski
Very nice Andrzej,

It is clear I need to study Mathematica more.

--Thanks,
V


  • References:
    • On Reduce
      • From: Virgil Stokes <vs@it.uu.se>
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