T
trantantai123


1.
cotx-i=(icos2x)/(1+tanx)+sin^2 (x)-0,5sin2x.
2.
[tex]\left\{ \ x-1/x=y- 1/y \\ 2y=x^3+1 [/tex]
cotx-i=(icos2x)/(1+tanx)+sin^2 (x)-0,5sin2x.
2.
[tex]\left\{ \ x-1/x=y- 1/y \\ 2y=x^3+1 [/tex]