Cos^6 α + sin^6 α+ 3cos^2 α * sin^2 α - вопрос №3661566322 от 777772018777777 14.02.2020 09:33

Question

Алгебра: Cos^6 α + sin^6 α+ 3cos^2 α * sin^2 α

777772018777777 · Answer

cos^6 α + sin^6 α+ 3cos^2 α * sin^2 α=

=(cos^2 α + sin^2 α)(cos^4 α + sin^4 α -cos^2 α * sin^2 α)+3cos^2 α * sin^2 α=

=1*(cos^4 α + sin^4 α -cos^2 α * sin^2 α)+3cos^2 α * sin^2 α=

cos^4 α + sin^4 α -cos^2 α * sin^2 α+3cos^2 α * sin^2 α=

cos^4 α + sin^4 α +2cos^2 α * sin^2 α=

(cos^2 α + sin^2 α)^2=1