Le vendredi 22 septembre 2017 15:42:40 UTC+2, Natalie Ulrich a écrit :
>
> That is extremely helpful. Many thanks, and have a beautiful day!
>
Thanks !
Two notes :
1. This kind of question, which is more oriented at learning how to use
Sage than at reporting a problem with it or suggesting a new development,
is probably more useful when asked on ask.sagemath.org
2. Most potential answerers, being scholars/teachers/etc.., are wary of
"homework" questions, and won't answer them (maybe providing helpful
hints). Giving the context of the question and showing what parts of the
work you did yourself may help them choosing the right answer...
HTH,
--
Emmanuel Charpentier
>
> On Friday, September 22, 2017 at 7:03:38 AM UTC-5, Emmanuel Charpentier
> wrote:
>
>> Even more Pythonish, and more direct (no conversions, Sage will take care
>> of the (hairy !) exact arithmetics)...) :
>>
>> [s for s in solve([eq1, eq2, eq3],[x, y, z], solution_dict=True) if
>> all(map(lambda t:bool(t>0), s.values()))]
>>
>> [{z: 1/200000*sqrt(2496889) - 83/200000,
>> y: 1/200000*sqrt(2496889) - 83/200000,
>> x: -1/200000*sqrt(2496889) + 15083/200000}]
>>
>> HTH,
>>
>> --
>> Emmanuel Charpentier
>>
>> Le vendredi 22 septembre 2017 13:47:39 UTC+2, Emmanuel Charpentier a
>> écrit :
>>>
>>> Some may find my first answer a bit Lispish. More Pythonish :
>>>
>>> [[s.lhs()==s.rhs().n() for s in S] for S in solve([eq1, eq2, eq3],[x, y,
>>> z])]
>>> [[x == 0.0675142263037092, y == 0.00748577369629076, z ==
>>> 0.00748577369629076],
>>> [x == 0.0833157736962908, y == -0.00831577369629076, z ==
>>> -0.00831577369629076]]
>>>
>>> HTH,
>>>
>>> --
>>> Emmanuel Charpentier
>>>
>>> Le vendredi 22 septembre 2017 13:40:45 UTC+2, Emmanuel Charpentier a
>>> écrit :
>>>>
>>>> what's wrong with :
>>>>
>>>> map(lambda S:map(lambda s:s.lhs()==s.rhs().n(), S), solve([eq1, eq2,
>>>> eq3], [x, y, z]))
>>>>
>>>> [[x == 0.0675142263037092, y == 0.00748577369629076, z ==
>>>> 0.00748577369629076],
>>>> [x == 0.0833157736962908, y == -0.00831577369629076, z ==
>>>> -0.00831577369629076]]
>>>>
>>>> Which shows that the first solution fulfills your constraints ?
>>>>
>>>> HTH,
>>>>
>>>> --
>>>> Emmanuel Charpentier
>>>>
>>>> Le jeudi 21 septembre 2017 20:27:43 UTC+2, Natalie Ulrich a écrit :
>>>>>
>>>>> I'm using SageMathCell to solve chemical equilibrium problems, so at
>>>>> least one set of my solutions has to be real and positive.
>>>>>
>>>>> Here's my code:
>>>>>
>>>>> var('x, y, z')
>>>>>
>>>>> xi=0
>>>>>
>>>>> yi=0.150/2.0
>>>>>
>>>>> zi=0.150/2.0
>>>>>
>>>>> K=8.3e-4
>>>>>
>>>>> eq1=K == y*z/ x
>>>>>
>>>>> eq2=xi+yi==x+y
>>>>>
>>>>> eq3=2*xi+2*zi==2*x+2*z
>>>>>
>>>>> solve([eq1, eq2, eq3],[x, y, z])
>>>>>
>>>>>
>>>>>
>>>>> And here are my solutions:
>>>>>
>>>>> [[x == -1/200000*sqrt(2496889) + 15083/200000, y ==
>>>>> 1/200000*sqrt(2496889) - 83/200000, z == 1/200000*sqrt(2496889) -
>>>>> 83/200000], [x == 1/200000*sqrt(2496889) + 15083/200000, y ==
>>>>> -1/200000*sqrt(2496889) - 83/200000, z == -1/200000*sqrt(2496889) - 83/
>>>>> 200000]]
>>>>> ------------------------------
>>>>>
>>>>>
>>>>> Any thoughts? Thanks in advance.
>>>>>
>>>>>
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