Arctg(tg45π/7) помогите

Question

Arctg(tg45π/7) помогите

Answer 1

Arctg(tgx)=x
arctg(tg45π/7)=arctg[tg(6π+3π/7)])=arctg(tg3π/7)=3π/7

Answer 2

Arctg(tg45π/7)=arctg(tg3π/7)=3π/7