Answer:
cos(pi/2) + i sin (pi/2)
Explanation:
(1+i)/ (1-i)
Multiply top and bottom by (1+i)
(1+i) (1+i)/ (1-i)(1+i)
Foil the top (1+i)(1+i) = 1 +2i +i^2 = 1 +2i -1 = 2i
Foil the bottom ( 1+i)(1-i) = 1 - i^2 = 1 - (-1) =2
2i/2 = i
the magnitude is (0^2+1^2) = 1
The angle is tan^-1( 1/0) = pi/2
cos(pi/2) + i sin (pi/2)