Consider the function f defined over the region ohm C 0 fz
     Consider the function f defined over the region ohm = C - {0}  f(z) = 1/z, (z  ohm)  (a) Is ohm simply connected?  (b) Let Gamma be the unit circle in ccd; whence, it is a simple closed curve in ccd that lies wholly in ohm. What is the value of the integral  integral_Gamma 1/z dz?  If ohm was simply connected what would you expect it to be? 
  
  Solution
Sigma is not simple conneted since a hole (origin) is there in the given region
(b) The integarl value is 2pi* i
If the sigma is simple connected then the integral value is Zero

