deTaylor

[salvomic]

(05-22-2015 09:44 PM)fhub Wrote:  Well, in the meantime you could also use the following function:

Code:


deLinSubst(f,x,y):=
...

Works only for ODEs of the type y'=f(a*x+b*y+c) with a,b,c=const.
For your example y'=(x+y)^2 just enter:
deLinSubst((x+y)^2,x,y)
(enter only the RHS, not y'=...)

In this simple form you get a solution only if Xcas can 'solve' the equation for y, but it could easily be modified to return at least an implicit solution if the equation is unsolvable.

Franz

well done, Franz!
it works: gives the true (general) solution of ODE y'=(x+y)^2 -> TAN(G_0+x)-x

Salvo