Maxima doesn't find an expected solution for a diff eq with desolve
Subject: Maxima doesn't find an expected solution for a diff eq with desolve
From: Michel Talon
Date: Tue, 29 Oct 2013 22:09:21 +0000 (UTC)
Marcus Menzel wrote:
> his result was:
> sol: y(t) = (m * sin(%omega*t)) / (%omega^2*c^2*r^2 + 1) -
> (%omega*c*m*r*cos(%omega*t)) / (%omega^2*c^2*r^2 + 1) +
> (%omega*c*m*r*%e^-((1*t)/(c*r))) / (%omega^2*c^2*r^2 + 1);
>
> my result is:
> y(t) = (m*sin(%omega*t))/(%omega^2*c^2*r^2+1) ?
> (%omega*c*m*r*cos(%omega*t))/(%omega^2*c^2*r^2+1) +
>
((y(0)*%omega^2*c^3*r^3+%omega*c^2*m*r^2+y(0)*c*r)*%e^(?t/(c*r)))/
> (c*r*(%omega^2*c^2*r^2+1))
>
His result doesn't depend on y(0) which should necessarily appear. Hence he
has probably chosen some particular value for y(0) and for this value both
results should be equal (probably y(0)=0).
--
Michel Talon