Tanza Kosta
Гений
(74762)
4 года назад
2sin²x + 3cosx - 3 = 0
2(1 - cos²x) + 3cosx - 3 = 0
2 - 2cos²x + 3cosx - 3 = 0
2cos²x - 3cosx +1 = 0
2(cosx - 1)(cosx - 1/2) = 0
cosx=1………… х=2pin, n€Z
cosx=1/2 …… х=±pi/4+2pik, k€Z
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7sin²x - 5cos²x + 2 = 0
7(1 - cos²x) - 5cos²x +2 = 0
7 - 7cos²x - 5cos²x + 2 = 0
-12cos²x + 9 = 0
4cos²x = 3
cos²x = 3/4
cosx = ± к3/2
Х= ±pi/6 + pin, n€Z