I have been working on this problem for a few days and dont know if what I'm doing is right. I work the problem using different methods and get different answers at this point I think I'm just confusing myself. The problem is F(z)= (3) / (z^2 + (1/9))....find inverse z. I first divided both sides by z and used partial frac exp to get the constants and then just looked at table for transform... The book has a similar problem with the inverse transform being time shifted by k-2 so this is where I'm confused. Any help would be greatly appreciated.