Question

Решить: 7 tg x – 10ctg x + 9 = 0

Answer 1

Ответ:

$7 tg x - 10ctg x + 9 = 0\\7tgx-\frac{10}{tgx} +9=0\\7tg^{2}x-10+9tgx=0\\t=tgx\\7t^{2} +9t-10=0\\D=81-(-4)*10*7=361\\t_{12} =-2; \frac{5}{7}; \\\\ tgx=-2\\x=-arctg(2)+nk, k=z\\tgx=\frac{5}{7} \\x=arctg(\frac{5}{7} )+nk, k=z$

Объяснение: