Question

вычислите: tg435+tg375

Answer 1

tg435+tg375=(375+475)tg=850tg

Answer 2

$tg435+tg375=frac{sin(435+375)}{cos435 cos375}=frac{sin810}{cos435 cos375}=frac{sin90}{cos75 cos15}$$=frac{1}{cos75 cos15}=frac{1}{frac{cos(75-15) +cos(75+15)}{2}}=frac{2}{cos60+cos90}=frac{2}{frac{1}{2}+0}=4$