Subject: help with evaluation of expression [newbie]
From: Panagiotis Papasotiriou
Date: Wed, 26 Oct 2011 14:49:47 +0300
Welcome to Maxima.
2011/10/26 Hugo Coolens <coolens at kahosl.be>
> Thank you very much for the help offered
>
> sincerely,
> hugo
>
>
> On Wed, 26 Oct 2011, Panagiotis Papasotiriou wrote:
>
>
>>
>> 2011/10/26 Hugo Coolens <coolens at kahosl.be>
>> I thought the following expression would evaluate as U_B, but
>> it doesn't
>>
>> limit((1/T)*integrate(U_B*(1-**e^(-t/tau)), t, 0,
>> T),T,inf,plus);
>>
>> maybe someone here can tell me how to proceed correctly.
>>
>> thanks in advance
>> hugo
>>
>>
>> You are missing a "%" before "e^(-t/tau)", and thus Maxima treats e as an
>> arbitrary variable, not the mathematical constant e=2.71828... Use
>>
>> limit((1/T)*integrate(U_B*(1-%**e^(-t/tau)), t, 0, T),T,inf,plus);
>>
>> Maxima will then ask you if tau is positive or negative; Answer
>> "positive", and you will get the result you are looking for. Another way
>> is to type:
>>
>> assume(tau>0);
>> limit((1/T)*integrate(U_B*(1-%**e^(-t/tau)), t, 0, T),T,inf,plus);
>>
>> so that you won't asked about tau.
>>
>>
>>