For the transformation w=(z+i)/(z-i)
show that as z moves along the real axis, w moves along a circle centre O and radius 1
I do not know where to start
changing it to polar form will help
w=magnitude @ (arctan 1/z - arctan -1/z)
where magnitude is sqrt (z^2+1)/(z^2+1)
w= 1 @ (2 arctan 1/z)
Is that a circle?
check my thinking.
I am really sorry but I do not understand your notation
please I need further help