Question

giai chi tiết giúp e với!!!

Answer 1

Pt \(\Leftrightarrow\left(cos^2x+sin^2x\right)^3-3cos^2x.sin^2x\left(cos^2x+sin^2x\right)=1-2sin^22x\)

\(\Leftrightarrow1-\dfrac{3}{4}sin^22x=1-2sin^22x\)

\(\Leftrightarrow\dfrac{5}{4}sin^22x=0\)\(\Leftrightarrow sin2x=0\Leftrightarrow x=\dfrac{k\pi}{2}\) \(\left(k\in Z\right)\)

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