36.
\(2sin^23x+5sin3x+2=0\)
\(\Leftrightarrow\left(2sin3x+1\right)\left(sin3x+2\right)=0\)
\(\Leftrightarrow2sin3x+1=0\)
\(\Leftrightarrow sin3x=-\dfrac{1}{2}\)
\(\Leftrightarrow\left[{}\begin{matrix}3x=-\dfrac{\pi}{6}+k2\pi\\3x=\dfrac{7\pi}{6}+k2\pi\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{\pi}{18}+\dfrac{k2\pi}{3}\\x=\dfrac{7\pi}{18}+\dfrac{k2\pi}{3}\end{matrix}\right.\)
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