Question

\(√3 sin4x-cos4x-√3 sin2x-cos2x+7=0\)

Giúp e với

Answer 1

\(pt\Leftrightarrow\frac{\sqrt{3}}{2}sin4x-\frac{1}{2}cos4x-\left(\frac{\sqrt{3}}{2}sin2x+\frac{1}{2}cos2x\right)+\frac{7}{2}=0\)

\(\Leftrightarrow-cos\left(4x+\frac{\pi}{3}\right)-sin\left(2x+\frac{\pi}{6}\right)+\frac{7}{2}=0\)

\(\Leftrightarrow-\left(1-2sin^2\left(2x+\frac{\pi}{6}\right)\right)-sin\left(2x+\frac{\pi}{6}\right)+\frac{7}{2}=0\)

\(\Leftrightarrow2sin^2\left(2x+\frac{\pi}{6}\right)-sin\left(2x+6\right)+\frac{5}{2}=0\left(VN\right)\)

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