05Jan

помогите)))) cos^4 π/12-sin^4 π/12

Kol1an Алгебра 1 15

помогите)))) cos^4 π/12-sin^4 π/12

Posted by Kol1an | Posted at Jan 05, 2014 | Categories: Алгебра

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Ингир
Ингир

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. 

Jan 05, 2014 08:57

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