Вычислить: tg435+tg375: по понятнее

[tex]tg435+tg375=\frac[sin(435+375)]
{cos435
cos375}=\frac{sin810}{
cos435
cos375=\frac{90}{cos75
cos15}[\tex][tex]=\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[\tex]