Предмет: Алгебра, автор: gr4ndmeister

cos(pi/12)
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Ответы

Автор ответа: Аноним
1

\cos \dfrac{\pi}{12}=\cos \left(\dfrac{\pi}{3}-\dfrac{\pi}{4}\right)=\cos \dfrac{\pi}{3}\cos\dfrac{\pi}{4}+\sin\dfrac{\pi}{3}\sin\dfrac{\pi}{4}=\dfrac{1}{\sqrt{2}}\cdot \left(\dfrac{1}{2}+\dfrac{\sqrt{3}}{2}\right)=\\ \\ \\ =\dfrac{1+\sqrt{3}}{2\sqrt{2}}

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