√[1/2+1/2√(1/2+1/2cos2α)]
=√[1/2+1/2√(cos^2α)]
=√[1/2+1/2|cosα|]
= √[cos^2(α/2)]
=|cos(a/2)|;或
√[1/2+1/2√(1/2+1/2cos2α)]
=√[1/2+1/2|cosα|]
= √[sin^2(α/2)]
=|sin(a/2)|.