Question

$(cos15+sin15 ) ^{2}$
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Answer 1

Ответ:

$(cos15^\circ +sin15^\circ )^2=cos^215^\circ +2cos15^\circ \cdot sin15^\circ +sin^215^\circ =\\\\\\=(sin^215^\circ +cos^215^\circ )+2\, si15^\circ \cdot cos15^\circ =1+sin30^\circ =1+\dfrac{1}{2}=1\dfrac{1}{2}=1,5$