How to use Fricas to solve this ode?

[Nasser M. Abbasi]

I am learning the syntax of using Fricas to solve an ode. I am using 8.10 chapter in this link for reference

http://fricas.github.io/book.pdf 

I think I am entering it correctly, but it gives me an error. Fricas 1.3.6

y:=operator 'y
ode := x^3* D(y x, x)^2+x*D(y x, x)- y x=0
solve(ode, y, x)

 

   >> Error detected within library code:

   getlincoeff: not an appropriate ordinary differential equation

Does this mean Fricas can not solve nonlinear ode's and Am I making a syntax error somewhere?

Thanks

--Nasser

[Waldek Hebisch]

FriCAS can solve linear equations of "arbitrary" order (expect
troubles around order 4 or 5). It can solve nonlinear
equations of first order, but derivative must in linear
form. AFAICS your example can be rewriten as

ode := D(y x, x) = sqrt(y(x)/x^3 - D(y(x), x)/x^2)
solve(ode, y, x)

which gives "failed" because FriCAS does not know how
to solve this equation (but some other work after
solving for derivative).

Arguably, Fricas should automaticaly solve for derivative
(and some types of equations can be solved without
explicitely solving for derivative), but currently
this is not done.

--
Waldek Hebisch