a)cos^2(x) - 4cosx - 2x.sinx + x^2 + 3 = 0
b) sin4x - cos4x = 1+4can2.sin(x- $\pi$ /4)
c) 4sin(x/2+ $\pi$ /6).sin( $\pi$ /6 - x/2) = √3. sinx.(cos2x+cosx)(1+cot^2x)
d) [2.(1+cot2x.cotx)]/sin^2(x) + 1/cos^4(x) = 48
Loga
Sinh Học lớp 12
