Cos 2x - 6sinx cosx +3=0
cos^2 x-sin^2 x -6sinx cosx +3=0
cos^2 x-sin^2 x -6sinx cosx +3*(sin^2 x +cos^2 x))=0
2sin^2 x-6 sinx cosx + 4cos^2 x=0 однороое уравнение; |:cos^2 x≠0
2tg^2 x -6tgx +4=0
y=tgx; 2y^2 -6y +4=0
D/4=3^2 -2*4=9-8=1; y1=(3-1)/2=1; y2=(3+1)/2=2
tgx=1 ili tgx= 2
x=π/4 +πn x=arctg2+πn; n-celoe
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