Martin Rubey <[email protected]> writes: > Hi there! > > I wanted to integrate a second order nonlinear differential equation, > and fricas responded with the error "no a linear diffeq"... Is just the > error message misleading, or is it a bug?
I should add: ")tr" shows that solve indeed calls the solver for non-linear equations, as I wanted it too. Martin > (I admit that I'd be positively surprised if it would have an elementary > integral...) > > Martin > > (1) -> D := series([(1/(n+1)*binomial(2*n, n))^2 for n in 0..])$UFPS FRAC > POLY INT; > > Type: UnivariateFormalPowerSeries(Fraction(Polynomial(Integer))) > (2) -> P := 1 - recip D; > > Type: UnivariateFormalPowerSeries(Fraction(Polynomial(Integer))) > (3) -> Da := recip(1-a*P); > > Type: Union(UnivariateFormalPowerSeries(Fraction(Polynomial(Integer))),...) > (4) -> )expose RECOP > RecurrenceOperator is now explicitly exposed in frame frame1 > (4) -> eq := getEq first guessADE([Da.i for i in 0..50]) > > (4) > 2 3 2 2 3 2 ,, > (((16a - 16a)x + (- a + a)x )f(x) + 16a x - a x )f (x) > > + > 2 3 2 2 , 2 > ((- 32a + 32a)x + (2a - 2a)x )f (x) > > + > 2 2 2 2 , > (((32a - 32a)x + (- 3a + 3a)x)f(x) + 32a x - 3a x)f (x) > > + > 3 2 2 3 2 2 2 > ((4a - 8a + 4a)x - a + 2a - 1)f(x) + ((8a - 8a)x + a - 4a + 3)f(x) > + > (4a x + 2a - 3)f(x) + 1 > Type: Expression(Integer) > (5) -> f := operator 'f; > > Type: BasicOperator > (6) -> solve(eq, f, x) > > >> Error detected within library code: > parseLODE: not a linear ordinary differential equation -- You received this message because you are subscribed to the Google Groups "FriCAS - computer algebra system" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/fricas-devel?hl=en.
