11cos2a если cosa=0.6

[latex]11cos2 \alpha = 11(cos^2 \alpha -sin^2 \alpha ) \\ cos^2 \alpha =0.6^2=0.36 \\ sin^2 \alpha =1-cos^2 \alpha = 1-0.36=0.64 \\ 11(cos^2 \alpha-sin^2 \alpha ) =11(0.36-0.64) = -3.08[/latex] ИЛИ [latex]11cos2 \alpha =11(2cos^2 \alpha -1) \\ cos^2 \alpha =0.6^2=0.36 \\ 11(2cos^2 \alpha -1)=11(2*0.36-1) = 11(0.72-1) = -3.08[/latex]