10 sin 2 x + 2 3 sin x cos x + 4 cos 2 x = 7 10 sin 2 x + 2 3 sin x cos x + 4 cos 2 x 7 cos 2 x 7 sin 2 x = 0 3 sin 2 x + 2 3 sin x cos x 3 cos 2 x = 0 3 tan 2 x + 2 3 tan x 3 = 0 tan x 12 = 3 ± ( 3 ) 2 + 9 3 = 3 ± 12 3 = 3 ± 2 3 3 { tan x 1 = 3 + 2 3 3 = 3 x 1 = π 3 + k π tan x 2 = 3 2 3 3 = 3 3 x 2 = π 6 + k π 10 sin^2 x + 2 sqrt 3 sin x cos x + 4 cos^2 x = 7 newline newline 10 sin^2 x + 2 sqrt 3 sin x cos x + 4 cos^2 x - 7 cos^2 x - 7 sin^2 x = 0 newline newline 3 sin^2 x + 2 sqrt 3 sin x cos x -3 cos^2 x = 0 newline newline 3 tan^2 x + 2 sqrt 3 tan x -3 = 0 newline newline tan x_12= { sqrt 3 +- sqrt{(sqrt 3 )^2+9} } over {3} = { sqrt 3 +- sqrt{12} } over {3}={ sqrt 3 +- 2 sqrt{3} } over {3} toward "" newline newline toward left lbrace stack{tan x_1 = { sqrt 3 + 2 sqrt{3} } over {3} = sqrt 3 toward x_1 ={ %pi over 3} + k %pi # tan x_2 ={ sqrt 3 - 2 sqrt{3} } over {3} =- {sqrt 3 over 3} toward x_2= -{ %pi over 6} + k %pi } right none