(1 + i)/(2 - i) = [(1 + i)(2 + i)] / [(2 - i)(2 + i)] =
= (2 + 3i - 1) / (4 + 1) = (1 + 3i)/5 = 1/5 + 3i/5
Представим в тригонометрической форме
1/5 + 3i/5 = r(cos fi + i*sin fi)
r = √[(1/5)^2 + (3/5)^2] = √(1/25 + 9/25) = √(10/25) = √10/5
tg fi = (3/5) / (1/5) = 3
1/5 + 3i/5 = √10/5*(cos(arctg 3) + i*sin(arctg 3))
В показательной форме
1/5 + 3i/5 = r*e^(i*fi) = √10/5*e^(i*arctg 3)