basic q regarding discrete exponential graph

[vaish_me]

hey.. if exponential signal=c*(alpha to the power n).. then according to the book its given if alpha is negative then the graph alternates between negative values and alpha is defined as (e to the power of beta*n).. and it is defined for a real exponent signal.

i have a doubt as to how the value of alpha can become negative when it is e to the power of a real number?


thanks for the replies..

 

[_Eduardo_]

If alpha is negative then the power of e must be complex.

--> beta = ln(|alpha|)+i