# [✓] Inverse Z-Transform - different solutions for the same polynom?

GROUPS:
 Hello everyone. I wrote this command on Wolfram Alpha: InverseZTransform[1/(1-a*(z^-1))] and InverseZTransform[z/(z-a)] http://www.wolframalpha.com/input/?i=InverseZTransform%5B1%2F(1-a*(z%5E-1))%5D+and+InverseZTransform%5Bz%2F(z-a)%5Dbut the solutions are different. Why? The polynom is the same in both cases. The right solution is a^n.Thank you very much.
 Michael Rogers 2 Votes They're equivalent, if n is an nonnegative integer.