Toán Lớp 11: Giải phương trình
2sin²x – sinx – 3 = 0
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Toán Lớp 11: Giải phương trình
2sin²x – sinx – 3 = 0
Comments ( 2 )
2{\sin ^2}x – \sin x – 3 = 0\\
\Leftrightarrow \left( {2\sin x – 3} \right)\left( {\sin x + 1} \right) = 0\\
\Leftrightarrow \left[ \begin{array}{l}
\sin x = \dfrac{3}{2}(L)\\
\sin x = – 1(tm)
\end{array} \right. \Rightarrow \sin x = – 1\\
\Rightarrow x = – \dfrac{\pi }{2} + k2\pi \left( {k \in \mathbb Z} \right)
\end{array}$