$2 sin^2 x = 2 + sinx cot x$
$2 sin^2 x = 2 + sinx \frac{cos x}{sin x} $
$2 sin^2 x = 2 + cos x $
$0 = 2 - 2 sin^2 x + cos x $
$0 = 2(1 - sin^2 x) + cos x $
$0 = 2 cos^2 x + cos x $
$0 = cos x (2 cos x + 1)$
$cos x = 0 \Rightarrow x = 90^\circ $
$cos x = -\frac{1}{2} \Rightarrow x = 120^\circ $ ไม่อยู่ในขอบเขตที่โจทย์กำหนด
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