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

Question

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

Answer 1

(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

Comments

sin(pi/6)= 1/2 , во втором примере