[latex]tg \frac{20 \pi }{3} =[/latex] [latex]tg \frac{28 \pi }{3} =[/latex] [latex]tg(- \frac{31 \pi }{6} )= [/latex] [latex]ctg \frac{16 \pi }{3} [/latex]

tg[latex] \frac{20*pi}{3} [/latex]=tg(7π-[latex] \frac{pi}{3} [/latex]) =-tg[latex] \frac{pi}{3} [/latex]=-√3 tg[latex] \frac{28*pi}{3} [/latex]=tg(9π+[latex] \frac{pi}{3} [/latex]) =tg[latex] \frac{pi}{3} [/latex]=√3 tg(-[latex] \frac{31*pi}{6} [/latex])=-tg[latex] \frac{31*pi}{6} [/latex]=-tg(5π+[latex] \frac{pi}{6} [/latex])=-tg[latex] \frac{pi}{6} [/latex]=-[latex] \frac{1}{ \sqrt{3} } [/latex] ctg[latex] \frac{16*pi}{3} [/latex]=ctg(5π+[latex] \frac{pi}{3} [/latex])=ctg[latex] \frac{pi}{3} [/latex]=[latex] \frac{1}{ \sqrt{3} } [/latex]