3sin^2x-2sinx+2=0 3sin^2x-sin2x+2=0 am nevoie urgent dau coroana

3sin²x-2sinx+2=0
Замена
sinx = a
3a²-2a+2=0
D = 4 - 4*3*2 = -20
x ∉ R
3sin²x - sin2x + 2  = 0
3sin²x - 2sinxcosx +2sin²x + cos²x = 0
5sin²x - 2sinxcosx +cos²x = 0
5tg²x - 2tgx + 1 = 0
Замена
tgx = a
5a² - 2a + 1 = 0
D = 4 - 4*5*1 = -16 
x∉R