Question

помогите пожалуйста срокчно(

Answer 1

$2sin^22 alpha +2cos( frac{ pi }{2} - alpha )+2cos^22 alpha =2(sin^22 alpha +cos^22 alpha )+2sin alpha = \ \ =2+2sin alpha =2+2sin frac{ pi }{6} =2+2* frac{1}{2} =3$

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$frac{cos^262+cos^228}{4} - frac{1}{2} cos60= frac{cos^2(90-28)+cos^228}{4}- frac{1}{2} * frac{1}{2} = \ \ = frac{sin^228+cos^228}{4} - frac{1}{4} = frac{1}{4} - frac{1}{4} =0$

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$frac{6 sqrt{3}sin15cos15 }{2cos^215-1} = frac{3 sqrt{3}sin30 }{cos^215+cos^215-1}= frac{3 sqrt{3} frac{ 1}{2} }{cos^215-sin^215} = frac{3 sqrt{3} }{2cos^230} = frac{3 sqrt{3} }{2 frac{ sqrt{3} }{2} } =3$