symbolic roots of 8th order polynomial

Hi!

I want to find symbolic roots of

                                                      expr := (A^2 * B^2 * Pi^4) + (2*A*B*C^2*Pi^2) Z^4 + (D*L^4) Z^6  + L^4 Z^8

  i tried in maple

Rootof(expr) ;

allvalues(%);

and it gives unexpected lengthy results.

To me maple works fine uptil 3rd order polynomial, but my expression is 8th order.

can the roots be found analytically?

regards

riz