I try to solve Zout for this BJT small-signal model but I find
RC || (ro + RE)
because Zout is calculated with Ib = 0 => βIb = 0.
From this link too Vin was calculated.
But the expression for Zo given in the book by Boylestad and Nashelsky is:
Zo = RC || (ro + β (ro + re) / (1 + β re / RE)])
Can you explain how to derive this?