Question

Решить неравенство arctgx≥π3
Ответ:
1) [√3/3; +∞)
2) [1; +∞)
3) (−∞; √3/3]
4) [√3; +∞)
5) (−∞; √3]

Answer 1

$arctgxgeq frac{pi}{3}\\tg(arctgx)geq tgfrac{pi}{3}\\xgeq sqrt3\\xin [, sqrt3;+infty )$