Question

решите)))))))))))))

Answer 1

tg9-tg63+tg81-tg27 = = tg9+tg81-(tg27+tg63) == tg9+tg(90-9) - (tg27+tg(90-27)) == tg9+Ctg9 - (tg27+Ctg) == 1/(cos9*sin9)-1/(cos27*sin27) == 2/sin18 - 2/sin54 == 2*(sin54-sin18)/(sin18*cos36) == 2*2*sin18*cos36/(sin18*cos36) = 4