Bạn tham khảo:
$2sin^{2x}-5sinx+2=0$
\(\left[ \begin{array}{l}sinx=2\\sinx=\dfrac{1}{2}\end{array} \right.\)
\(\left[ \begin{array}{l}sinx=2(L)\\sinx=\dfrac{1}{2}(N)\end{array} \right.\)
$sinx=\dfrac{1}{2}$
$sinx=sin\dfrac{\pi}{6}$
\(\left[ \begin{array}{l}x=\dfrac{\pi}{6}+k2\pi\\x=\pi-\dfrac{\pi}{6}+k2\pi=\dfrac{5\pi}{6}+k2\pi\end{array} \right.\)
$S=\{\dfrac{\pi}{6}+k2\pi; \dfrac{5\pi}{6}+k2\pi | K∈Z\}$
