desolve question



>Hello,
>I get this and don't know how to handle it.
>
>                               3
>                              d              2
>(D11)                         --- (f(z)) = ------
>                                3               2
>                              dz           1 - z
>(C12) desolve(d11,f(z));
                                                                  
This isn't the most elegant solution but
I got some results by reducing the order
and using ode2 (which only works on 1st and 2nd order DEs).
                                                                    
depends(f3,z)$
u3:ODE2(DIFF(f3,z,1) = 1/(1-z^2),f3,z);
                                                                      
                            LOG(z + 1)   LOG(z - 1)
(D3)                   f3 = ---------- - ---------- + %C
                                2            2
                                                                       
The right hand side of u3 can be referenced as rhs(u3).
(can also use rhs(d3) but rhs(f3) doesn't work.)
                                                                      
depends(f2,z)$
u2:ODE2(DIFF(f2,z,1) = rhs(u3),f2,z)$
                                                                       
depends(f1,z)$
u1:ODE2(DIFF(f1,z,1) = rhs(u2),f1,z);
                                                                       
The answer is in u1. Check the results:
                                                                        
 diff(rhs(u1),z,3);
 ratsimp(%);
                                       1
(D9)                               - ------
                                      2
                                     z  - 1
                                                                                       
lp