Complex functions

[Jerbearrrrrr]

Hi, just wondering where this line comes from

http://img514.imageshack.us/img514/4990/complq.jpg

Here's my beef:

If we evaluate it at z=z_0, why are there still 'z's in (2.11)?
Furthermore, isn't the congujate of f=u( )+iv( ) simply u( )-iv( )?

The formula seems to have been evaluated at z* = z*_0.

Not sure what's going on.
Thanks
[edit]
If this belongs in the homework thing forum place, sorry. Please move it.

[luma]

if z = z_0 in eq. 2 then it makes sense.

f*(z) =/= f(z*)

seems correct. not sure what the question is :p

[Jerbearrrrrr]

Why are there still z's in the 2nd equation?
as in, shouldn't they all be z_0s now?

[edit]
I think the author has 'barred' the arguments because they are real, after setting z=z_0 and leaving z* as it is.