I tried rootscontract on factor(e) and it did return 0.
H.T.H.
Milan
* Barton Willis <willisb at unk.edu> [2007-01-11 18:20:33 -0600]:
>
> (%i125) (r-1)*(r+2)^2 = 16*t^2$
> (%i126) rhs(last(solve(%,r)))$
> (%i127) e : %-subst(t=-t,%)$
>
> For real t, the expression e vanishes. Is there a way to get
> Maxima to crunch it to zero? One term of factor(e)
> looks like junk^(1/3) * mess^(1/3) - 1. And junk * mess = 1,
> but what Maxima command does junk^(1/3) * mess^(1/3) ->
> (junk * mess)^(1/3)?
>
> Barton
>
> PS. For a planet in parabolic orbit (inverse square law force),
> the equation (r-1)*(r+2)^2 = 16*t^2 determines the radial distance
> as a function of time.
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