Помогите))))cos^4 π/12-sin^4 π/12

Question

Помогите))))
cos^4 π/12-sin^4 π/12

Answer 1

Сos⁴(π/12) - sin⁴(π/12) = (cos²(π/12) - sin²(π/12))(cos²(π/12) + sin²(π/12)) = 1(cos²(π/12) - sin²(π/12)) = cos²(π/12) - sin²(π/12)) = cos(2·π/12) = cos(π/6) = √3/2.