R
ruacondangyeu


[TEX]2. cot x + sin x ( 1+ tan x.tan x/2) = 4[/TEX]
[TEX]3. tan^2 x + cot^2 x + cot^2 2x = 11/3 [/TEX]
[TEX]4. [3 (sin x +tan x) / (tan x - sin x)] - 2 cos x = 2 [/TEX]
[TEX]5. 2 sin 3x (1 -4 sin^2 x ) =1 [/TEX]
[TEX]6. 2 tan x + cot 2x = 2 sin 2x + 1/ sin 2x[/TEX]
[TEX]7. (1 - tan x) (1 + sin 2x) = 1 + tan x[/TEX]
[TEX]8. 9 sin x+ 6 cos x - 3 sin 2x + cos 2x = 8[/TEX]
mog mọi người giúp đỡ!