Question: Complicated solution of dsolve with RootOf(_Z)

Hello,

I would like to solve this equation and keep the parameters a and eta unknown and assign them a value later on. Is it possible ?

I know I can solve this equation numerically, it works, but I want to change the parameters to fit experimental data.

I tried this :

ode:=diff(y(t),t)=-(4/3)*(a/eta)*(y(t)^3+1):
lambdaE:=dsolve({ode,y(0)=1},y(t),explicit);

But the solution appears with RootOf expression and I can't get a numerical solution afterwards.

lambdaE := y(t) = RootOf(6*eta*sqrt(3)*arctan(((2*_Z - 1)*sqrt(3))/3) - eta*sqrt(3)*Pi - 3*eta*ln(_Z^2 - _Z + 1) + 6*eta*ln(_Z + 1) - 6*eta*ln(2) + 24*t*a)

I tried some things from forums but nothing works.

Do you have any leads on how to do it please ?

Thank you in advance

Manon