I think this is probably because you did not know how to type a complex number in R. The coefficient of i is not optional. > exp(-2 * atan(1)) [1] 0.20

I think this is probably because you did not know how to type a complex number in R. The coefficient of i is not optional. > exp(-2 * atan(1)) [1] 0.2078796 > 1i ** 1i [1] 0.2078796+0i