Question

Срочно надооо пж... ​

Answer 1

$ctg(arcctg(-2,5))+tg(arctg3)+arcctg(tgfrac{3pi}{9})=\\=-2,5+3+arcctgBig(tg(frac{pi}{2}-frac{pi}{6})Big)=\\=0,5+arcctg(ctgfrac{pi}{3})=0,5+frac{pi}{3}approx 0,5+1,05=1,55$