I think that it must be when
f(z) divided by (z-i) and (z+i)
f(i)=i
f(-i)=1+i
on dividing f(z) z^2+1 ;we will get a equation as remainder
let g(z) be quotient & az +b as remainder
f(z)=g(z).(z^2+1) + az+b
f(z)=g(z).(z+i)*(z-i) + az+b
f(i) = ai + b = i
f(-i) = -ai + b=1+i
On soling the equations given above we will get :-
b=(1+2i)/2 and a=-1/2i=i/2
remainder=(i.z)/2+1/2+i
remainder= zi/2 + (1/2 +i).
Hope you get it .
Cheers!!!!!!!!!!!!!!!!!!!!
