Cos2x+ 5sinxcosx +5cos^2x=0
Cos2x+0.5=cos²x cos²x-sin²x+0.5=cos²x sin²x=0.5 sinx=±1/√2 x₁=(-1)^n•π/4+πn x₂=-(-1)^n•π/4+πn Какой-то так :)
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