(sin pi/8 - cos pi/8)^2 =?
(sin pi/12 + cos pi/12)^2=?

sin(pi/6)= 1/2 , во втором примере

(sin pi/8 - cos pi/8)^2 =sin²π/8+cos²π/8-2sinπ/8cosπ/8=1-sinπ/4=1-√2/2==(2-√2)/2(sin pi/12 + cos pi/12)^2=sin²π/12+cos²π/12+2sinπ/12cosπ/12=1+sinπ/6==1+1/2=1,5