Phương trình tương đương với: \({\sin ^6}x\left( {1 - 2{{\sin }^2}x} \right) + c{\rm{o}}{{\rm{s}}^6}x\left( {2{{\cos }^2}x - 1} \right) = 0\) \( \Leftrightarrow c{\rm{os}}2x\left( {c{\rm{o}}{{\rm{s}}^6}x + {{\sin }^6}x} \right) = 0 \Rightarrow c{\rm{os}}2x = 0\)\( \Leftrightarrow x = \frac{\pi }{4} + k\frac{\pi }{2}\)
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arrow {\sin ^6}x\left( {1 - 2{{\sin }^2}x} \right) + c{\rm{o}}{{\rm{s}}^6}x\left( {2{{\cos }^2}x - 1} \right) = 0\) \( \Leftrightarrow c{\rm{os}}2x\left( {c{\rm{o}}{{\rm{s}}^6}x + {{\sin }^6}x} \right) = 0 \Rightarrow c{\rm{os}}2x = 0\)
\( \Leftrightarrow x = \frac{\pi }{4} + k\frac{\pi }{2}\)