Вычислите tg x, если tg (x - 45) = 3

Question

Вычислите tg x, если tg (x - 45) = 3

Answer 1

tg(x-y) = (tgx - tgy)/(1 + tgx*tgy)

 tg (x - 45) = (tgx - tg45)/(1 + tgx*tg45) = (tgx - 1)/(1 + tgx) = 3

tgx - 1 = 3 + 3tgx

2tgx = -4

tgx = -2