Identities

[matt.ware0476]

Hello, this is my first time using a forum so will give the best information I can.

Im on the tail end trying to solve a bilinear equation using Li Tan's book Digital signal processing: fundementals and applications (i will metion at this point, yes it is an assignment question).

I have managed up to the point pictured below where i cannot transorm the upper denominator to the lower denominator.



Any help, advise or a general point to some background reading will be very much appriciated.

Thankyou in advance

 

[Dr.Peterson]

I don't see that you'd use any identities to get from the first form to the second; I'd suspect that they were used to obtain the first.

To get to the second, just expand, that is, distribute over the parentheses and combine like terms. Nothing special is needed.