On 28/05/2013 1:52 PM, Alasdair McAndrew wrote:
> If I want to solve the ivp
>
> y' = y(1-y), y(0)=1/2
>
> (a logistic equation), I can use either
>
> ic1(ode2('diff(y,x)=y*(1-y),y,x),x=0,y=1/2);
>
> or
>
> ic1(contrib_ode('diff(y,x)=y*(1-y),y,x),x=0,y=1/2);
>
> both of which give me as a solution
>
> log(y)-log(y-1) = x - log(2) - log(-1/2)
>
> instead of
>
> y = exp(x)/(exp(x)+1).
>
> I can obtain this solution by some fiddling with Maxima's output, but
> is there any way of obtaining the "correct" solution directly?
>
> Thanks,
> Alasdair
>
Not easily :-(. I couldn't find a good, general solution when I wrote
contrib_ode, so I gave up.