高二數學,化簡sin平方(20度+θ)+sin平方(70度-θ)+cos平方(40度+θ+cos平方(50度-θ)?

Sin^2 (20度+θ)+Sin^2 (70度－θ)+Cos^2 (40度+θ)+Cos^2 (50度－θ)
=Sin^2 (20度+θ)+Cos^2 (20度+θ)+Cos^2 (40度+θ)+Sin^2 (50度－θ)
=1+1
=2

sin^2 (20度+θ)+sin^2 (70度－θ)+cos^2 (40度+θ)+cos^2 (50度－θ)
=sin^2 (20+θ)+cos^2 [90-(70度-θ)]+cos^2 (40度+θ)+sin^2 [90-(50度－θ)]
=sin^2 (20+θ)+cos^2 (20+θ)+cos^2 (40度+θ)+sin^2 (40度+θ)
=1+1
=2