1) \(2sin^2x-5sinx-3=0\Rightarrow\left\{{}\begin{matrix}sinx=3\left(l\right)\\sinx=-\dfrac{1}{2}\end{matrix}\right.\)
\(\Rightarrow sinx=sin\left(-\dfrac{\pi}{6}\right)\) \(\Rightarrow\left[{}\begin{matrix}x=-\dfrac{\pi}{6}+k2\pi\\x=\dfrac{7\pi}{6}+k2\pi\end{matrix}\right.\) (k\(\in\)Z)
2) \(\sqrt{3}cot^2x-4cotx+\sqrt{3}=0\)
Đk: \(x\ne m\pi\)
Pt; \(\Rightarrow\left[{}\begin{matrix}cotx=\sqrt{3}\\cotx=\dfrac{\sqrt{3}}{3}\end{matrix}\right.\) bạn tự tìm x nhé
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