(sin²α+tg²α*sin²α)ctgα=sin²α*(1+tg²α)ctgα=sin²α*(1/cos²α)ctgα=()()=
(tg²α)*(ctgα)=((tgα)*(ctgα))(tgα)=1*tgα=tgα
(sin²α+tg²α*sin²α)ctgα=sin²α*(1+tg²α)ctgα=sin²α*(1/cos²α)ctgα=()()=
(tg²α)*(ctgα)=((tgα)*(ctgα))(tgα)=1*tgα=tgα