Toán Lớp 11: a) sin2x – √3cos2x – √2 = 0.
b) 3cos2x + 2sin2x – 3sin2x = 0
c) 2cos2x + 1 = 0.
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Toán Lớp 11: a) sin2x – √3cos2x – √2 = 0.
b) 3cos2x + 2sin2x – 3sin2x = 0
c) 2cos2x + 1 = 0.
giải hộ mình nha
Comments ( 1 )
a) sin2x – √3cos2x = √2
Chia hai vế cho 2 : 1/2sin2x – √3/2cos2x = √2/2
sin(2x – π/3) = √2/2
2x – π/3 = π/4 + k2π x = 7π/24 + kπ
2x – π/3 = 3π/4 + k2π x = 13π/24 + kπ
b) 3cos2x + 2sin2x – 3sin2x =0
3cos2x – sin2x =0
3cos2x = sin2x
3cot2x = 1
cot2x = 1/3 2x = arccot(1/3) + kπ
x = arccot(1/3)/2 + kπ/2
c) 2cos2x + 1 =0
cos2x = -1/2
2x = ±π/3 + k2π
x = ±π/6 + kπ