19π/6.
Пошаговое объяснение:
4arccos(-√2/2) - 3arccos1 + 2arcsin1/2 - arctg√3/3 = 4•(π - arccos√2/2) - 3•0 + 2•π/6 - π/6 = 4•(π - π/4) - 0 + 2π/6 - π/6 = 3π + π/6 = 3 1/6•π (или 19π/6).
