Cosx -√3 sinx = 1
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3 câu trả lời 869
\(\begin{array}{l}
\cos x - \sqrt 3 \sin x = 1\\
\Leftrightarrow \frac{1}{2}\cos x - \frac{{\sqrt 3 }}{2}\sin x = \frac{1}{2}\\
\Leftrightarrow \sin \frac{\pi }{6}\cos x - \sin \frac{\pi }{6}\sin x = \frac{1}{2}\\
\Leftrightarrow \sin \left( {\frac{\pi }{6} - x} \right) = \sin \frac{\pi }{6}\\
\Leftrightarrow \left[ \begin{array}{l}
\frac{\pi }{6} - x = \frac{\pi }{6} + k2\pi \\
\frac{\pi }{6} - x = \pi - \frac{\pi }{6} + k2\pi
\end{array} \right.\\
\Leftrightarrow \left[ \begin{array}{l}
x = - k2\pi \\
x = \frac{{ - 2\pi }}{3} - k2\pi
\end{array} \right.\left( {k \in Z} \right)\\
vay:S = \{ - k2\pi ;\frac{{ - 2\pi }}{3} - k2\pi \}
\end{array}\)
cosx−√3sinx=1⇔12cosx−√32sinx=12⇔sinπ6cosx−sinπ6sinx=12⇔sin(π6−x)=sinπ6⇔[π6−x=π6+k2ππ6−x=π−π6+k2π⇔[x=−k2πx=−2π3−k2π(k∈Z)vay:S={−k2π;−2π3−k2π}
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