Question

докажите что верно равенство (sin x+cos x)^2=1+sin 2x

Answer 1

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Answer 2

$(sin x+cos x)^2=1+sin2x;\ (sin x+cos x)^2=sin^2x+2sin xcos x+cos^2x=\ =(sin^2x+cos^2x)+2sin xcos x=1+sin2x.$