[TI-M] Re: Can TI-89 do this math?
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[TI-M] Re: Can TI-89 do this math?
> I tried:
>
> integrate( e^(s*t)*t,t,0,infinity )
>
> which returned "undef" or maybe infinity, I forget. And I tried:
>
> integrate( e^(s*t)*sin(t),t,0,infinity )
>
> An astute reader will recognize that I made an error in that the Laplace
> transform should have a minus sign in the exponent of e. However, this
> has little effect on the outcome, as the result returned from the first
> integral should look something like:
>
> 1/s^2 if Re(s)>0, else undef
>
> and so the case of a positive exponent would simply cause the condition
> to be if Re(s)<0.
>
> Can the TI-89 accept assumptions that would make it return a result in
> this case?
I was hoping someone else who better understood the math here would respond,
but since no one has, I don't want to leave you in the dark. You can
usually specify assumptions, although I've only done it in simpler cases.
For example,
integrate( e^(s*t)*t,t,0,infinity ) | x>0
yields an answer of infinity instead of undef. But I see that still isn't
exactly what you're trying to do or want as an answer. I recommend you ask
on TI's discussion group at
<http://www-s.ti.com/cgi-bin/discuss/sdbmessage.cgi?databasetoopen=calculato
rs&topicarea=TI-89/Voyage+200/TI-92+Plus&do_2=1>; you're more likely to find
an answer there.
-Scott
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