pl=[2   0  1];
p2=[1   0   0   -1];
%Óìíîæåíèå ïîëèíîìîâ:   (2õ^2+1) (õ^3-1) = 2õ^5+õ^3-2õ^2-1
p=conv(p2,pl)
%Äåëåíèå ïîëèíîìîâ:   (2õ^5+õ^3-2õ^2-1) / (õ^3-1) = (2õ^2+1) 
deconv(p,p2) 