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]