[ครูนะ]

$2(1-(sin2x)^{2}) + 3sin2x - 3 = 0$

$2 - 2(sin2x)^{2} + 3sin2x - 3 = 0$

$-2(sin2x)^{2} + 3sin2x - 1 = 0$

$2(sin2x)^{2} - 3sin2x + 1 = 0$

$(2sin2x - 1)(sin2x - 1) = 0$

$sin2x = 1/2$

$sin4x = 2(sin2x)(cos2x)$

$sin4x = cos2x$

$sin4x = \sqrt{1 - (sin2x)^{2}}$

$sin4x = \frac{\sqrt{3}}{\sqrt{4}}$

บรรทัดสุดท้ายพิมพ์ไม่เป็น รูท3/4