if arg ab pi2 then find the value of aba-b where

Question

If arg (a/b) = pi/2, then find the value of ((a+b)/(a-b)) where a,b are complex numbers.

Ans) Arg (a/b) =Pi/2

Tan-1   (a/b)=   Pi/2

A/B = tanP/2 ,therefore a/b=infinity.

Or b=0

As per your question a+b/a-b= 1

As a and b are complex numbers the answer is "i"