11√3 * tg 7π/4 * cos 4π/6
11*sqrt(3) * tg 7π/4 * cos 4π/6 = 11*sqrt(3) * tg(π + 3π/4) * cos 2π/3 = = 11*sqrt(3) * tg 3π/4 * cos 2π/3 = 11*sqrt(3)*(-1)*(-1/2) = 11*sqrt(3)/2