а) 4arcsin(-√2/2) - 1/3 arcctg(-√3) =
= 4 · (-π/4) - 1/3 · 5π/6 =
= -π - 5π/18 =
= - 23π/18
б) cos(4arctg1 - arcsin(-1/2)) =
= cos (4 · π/4 + π/6) =
= cos 7π/6 =
= - 0.5√3
