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Ответ
6 tgx + cos^2x + 3sin2x = 1
6sin x/cos x + cos^2 x + 6sin x*cos x = 1
6sin x + cos^3 x + 6sin x*cos^2 x = cos x
6sin x + 6sin x*cos^2 x = cos x - cos^3 x
6sin a*(1 + cos^2 x) = cos x*(1 - cos^2 x)
6sin a*(1 + cos^2 x) = cos x*sin^2 x
6*(1 + cos^2 x) = sinx*cos x
2*6*(1 + cos^2 x) = 2sinx*cos x
2*6*(2 + 2cos^2 x) = 2sinx*cos x
2*6*[2 + (1 + cos 2x)] = 1 - cos 2x
12* (3 + cos 2x)] = 1 - cos 2x
12* (3 + cos 2x)] = 1 - cos 2x
36 + 12 cos 2x = 1 - cos 2x
13cos 2x = -35
cos 2x = -35/13
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