T
thanhhoawa


1] [tanx]^2 = [1 + [cos]^3] / [1 + [sin]^3]
2] [sĩnx]^2 * tanx + [cosx]^2 * cotx - sin2x = 1 + tanx + cotx
3] tan[x/2] * cosx - sin2x = 0
2] [sĩnx]^2 * tanx + [cosx]^2 * cotx - sin2x = 1 + tanx + cotx
3] tan[x/2] * cosx - sin2x = 0