N
nhokgaru96


1. ( tanx . cot2x-1).sin( π/2 +4x) = -1/2 ( sin^4x +cos^4X)
2. 2cos^3x= 2cosx + 2tanx + sinx.sin2x
3. sin(3π/10 - x/2) = 1/2 sin(π/10 + 3X/2)
mong các bạn giúp mình
2. 2cos^3x= 2cosx + 2tanx + sinx.sin2x
3. sin(3π/10 - x/2) = 1/2 sin(π/10 + 3X/2)