-10ctg(10*pi\9)/ctg(pi\9) с объяснением

Question

-10ctg(10*pi\9)/ctg(pi\9)
с объяснением

Answer 1

Решение
- 10ctg(10π/9) / ctg(π/9) = - 10*ctg(π + π/9) / ctg(π/9) =
 = - 10*ctg(π/9) / ctg(π/9) = - 10

Answer 2

-10ctg(π+π/9)/ctg(π/9)=-10ctg(π/9)/ctg(π/9)=-10