Question

Найти tg x, если cos2x=-1/3,  П  меньше 2x  меньше 3П/2

Answer 1

cos²x = (1+cos2x) / 2 = (1-1/3) /2 = 1/3
1 + tg²x = 1/cos²x
tg²x = 1/cos²x - 1 = 3 - 1 =2
tgx = √2