5arcsin 1/2 -9 arccos √3/2 +4 arctg 1

= 5*[latex] \frac{ \pi }{6} [/latex] - 9*[latex] \frac{ \pi }{6} [/latex] + 4*[latex] \frac{ \pi }{4} [/latex] = -4*[latex] \frac{ \pi }{6} [/latex] + π = [latex] \frac{-4 \pi +6 \pi }{6} [/latex] = [latex] \frac{2 \pi }{6} [/latex]=[latex] \frac{ \pi}{3} [/latex]