Doubt about rotation isometry on the complex plane

1. Nov 14, 2014

PcumP_Ravenclaw

Dear All,
In the 2nd paragraph of the attachment can you please explain to me why we are trying to make $r(z) = z$

and what does "As r is not the identity........" mean??

and how did the line $L = 0.5*b + ρe^{θ/2}$ come about?

Danke...

Attached Files:

• Capture.JPG
File size:
76.7 KB
Views:
77
2. Nov 15, 2014

HallsofIvy

Staff Emeritus
The second sentence starts "If (ii) Is true" so everything said here depends upon "(ii)" being true but we don't know what "(ii)" is!

3. Nov 15, 2014

PcumP_Ravenclaw

Oops sorry!!.

The missing scan is in this attachement.

danke.

Attached Files:

• Capture1.JPG
File size:
30.5 KB
Views:
70
4. Nov 21, 2014

Fredrik

Staff Emeritus
"r is not the identity" means "r is not the identity map", which means "r is not the unique function f such that f(z)=z for all z". So there's at least one complex number z such that r(z)≠z.