Answers to quiz 2

1. (2i)1/2 = 1+i, −1−i (Sect.14, Example 2)

2. If Re z = 0 then z = iy, cos iy = cosh y (Eq. 12.4) is a real number. If Im z = 0 then z = x, cos x is a real number. In both cases Im(cos z) = 0.

back to the course page