One of the values of ii  is

ii=[cos(π2+2rπ)+isin(π2+2rπ)]i,r=0,±1,±2  ..... [ei(π2+2rπ)]i=e−(π2+2rπ),    r=0,±1,±2,.........We get ii=e−π2  when r=0 ALTERNATE: let ii=a+ib⇒ilogi=log(a+ib)⇒i.iπ2=log(a+ib)    ∴a+ib=e−π2