ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Wed, 07 Apr 2021 14:49:01 +0200Maxima wants to know whether %k1 is positive or negativehttps://ask.sagemath.org/question/56526/maxima-wants-to-know-whether-k1-is-positive-or-negative/Trying to solve a differential equation in Sage:
sage: de = -diff(y, x, 2) - G*M/y^2
sage: desolve(de, y, ics=[0, 1000])
I get a type error and a question:
TypeError: Computation failed since Maxima requested additional constraints; using the 'assume' command before evaluation *may* help (example of legal syntax is 'assume(%k1>0)', see `assume?` for more details)
Is %k1 positive or negative?
But when I use `assume(%k1>0)` I get a syntax error,
saying that there's something wrong with the percent sign.Dr. BananaWed, 07 Apr 2021 14:49:01 +0200https://ask.sagemath.org/question/56526/Problems with LaPlace transform when 'a' is negative in e^-athttps://ask.sagemath.org/question/8908/problems-with-laplace-transform-when-a-is-negative-in-e-at/ var('s t')
f = t^(-1)*exp(-t)-t^(-1)*exp((-3)*t)
f.laplace(t,s)
The above transform works as expected, however, when (-3) is changed to (3), I get the following error:
Traceback (click to the left of this block for traceback)
...
TypeError: ECL says: Maxima asks: Is s-3 positive, negative, or zero?
The Solution that I am expecting is:
log((s - 3)/(s + 1))
I don't know how to specify if s-3 is positive, negative, or zero. Any ideas?
Thanks,
Taylor Killian
tkillianFri, 20 Apr 2012 00:39:03 +0200https://ask.sagemath.org/question/8908/