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Re: Reduce in Ver 6

  • To: mathgroup at smc.vnet.net
  • Subject: [mg85502] Re: Reduce in Ver 6
  • From: "Dana DeLouis" <dana.del at gmail.com>
  • Date: Wed, 13 Feb 2008 04:07:01 -0500 (EST)

> Use the Backsubstitution -> True setting for Reduce[]

Darn!  Yep!  Right there in help under Reduce.
Thank you very much.  I think I've been confusing this with the
"VerifySolutions" option under Solve.  I now understand my mistake.  Can't
believe I've missed this all this time.
Thanks again.

equ = {a + b + c == 3, a^2 + b^2 + c^2 < 10, 
a^3 + b^3 + c^3 == 15, a^4 + b^4 + c^4 == 35};

sol = {ToRules[Reduce[equ, {a, b, c}, 
       Backsubstitution -> True]]}; 

Simplify[a^5 + b^5 + c^5 /. sol]
{83, 83, 83, 83, 83, 83}

-- 
Dana DeLouis

<snip>

>> I use Reduce, but 'c is returned as a function of a & b.
>> What I would like is for c to replace a & b with the appropriate values.
>>
>> r = {ToRules[Reduce[equ, {a, b, c}]]}
>>
>> {{a -> 1, b -> 1 - Sqrt[2], c -> 3 - a - b},

 
> Use the Backsubstitution -> True setting for Reduce[]
> 
> Szabolcs






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