(a^3+1/a^3)(a^3-1/a^3)/[(a^4+1/a^4+1)(a-1/a)]
=(a^6-1/a^6)/[(a^4+1/a^4+1)(a-1/a)]
=[(a^2)^3-1/(a^2)^3]/[(a^4+1/a^4+1)(a-1/a)]
=[(a^2-1/a^2)*(a^4+1/a^4+1)]/[(a^4+1/a^4+1)(a-1/a)]
=(a^2-1/a^2)/(a-1/a)
=a+1/a