1
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cosx =\frac{3-5}{4}=-0.5
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x=\pm \frac{2 \pi }{3} +2 \pi n, \ n\in Z" alt="3^{3cosx-cos2x}= \frac{1}{3}
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3^{3cosx-cos2x}= 3^{-1}
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3cosx-cos2x=-1
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3cosx-cos^2x+sin^2x+1=0
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3cosx-cos^2x+1-cos^2x+1=0
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2cosx^2x-3cosx-2=0
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D=9+16=25
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cosx \neq \frac{3+5}{4}=2 >1
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cosx =\frac{3-5}{4}=-0.5
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x=\pm \frac{2 \pi }{3} +2 \pi n, \ n\in Z" align="absmiddle" class="latex-formula">
Ответ: 