Question

tg a=1/3" tg B=-2 tg(a+B)=?

Answer 1

$tg(a+b)= frac{tga+tgb}{1-tga*tgb}= frac{ frac{1}{3}+(-2) }{1- frac{1}{3}*(-2) } = frac{ -frac{5}{3} }{ -frac{1}{3} }=5$