content_image/316973.jpg content_image/316974.jpg
In (3.15), we used the equality Re ( iz ) = Im (¯ z ) . 

<img src='content_image/316973.jpg'>

In (3.16), we used the equality Re z$_{y}$$_{j}$ ¯ z$_{y}$$_{i}$$_{y}$$_{j}$ = 1 2 ( ∣ z$_{y}$$_{j}$ ∣ 2 ) y$_{i}$ . 

<img src='content_image/316974.jpg'>

