sin^2 (t/2) = (1 - cos t) / 2
1 - sin^2 22,5° = 1 - (1 - cos 45°) / 2 = 1 - (1 - √2/2) / 2 = 1 - (2 - √2)/4 =
= (2+√2)/4 = 1/2 + (1/4)√2
sin^2 (t/2) = (1 - cos t) / 2
1 - sin^2 22,5° = 1 - (1 - cos 45°) / 2 = 1 - (1 - √2/2) / 2 = 1 - (2 - √2)/4 =
= (2+√2)/4 = 1/2 + (1/4)√2