(1-i)^2(1+i)^2 = [(1^2 - 2i + i^2)(1^2 + 2i + i^2)]= [(1 - 2i + (-1))(1 + 2i + (-1))]= [(0 - 2i)(0 + 2i)]= [-4i^2]= [-4*(-1)]= 4.
(1-i)^2(1+i)^2 = [(1^2 - 2i + i^2)(1^2 + 2i + i^2)]
= [(1 - 2i + (-1))(1 + 2i + (-1))]
= [(0 - 2i)(0 + 2i)]
= [-4i^2]
= [-4*(-1)]
= 4.