Вычислите: а) 4arcsin(-√2/2) - 1/3 arcctg(-√3) ; б) cos(4arctg1 - arcsin(-1/2))
Заранее спасибо )

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