Question

Решите пример
$(tga+ctga)^2-(tga-ctga)^2$

Answer 1

(tgα+ctgα)²-(tgα-ctgα)²=tg²α+2tgα*ctgα+ctg²α-(tg²α-2tgα*ctgα+ctg²α)=

=tg²α+2*1+ctg²α-tg²α+2*1-ctg²α=4