Question

7 tg x – 10ctg x + 9 = 0

Answer 1

Объяснение:

7tgd-10ctgx+9=0

7tgx- 10/tgx + 9=0

7tg²x-20+9tgx=0

t=tgx

7t²+9t-10=0

D=81-(-4)*10*7=361

t(снизу 12) = -2; 5/7;

tgx=-2

x= - arctg(2) + nk, k = z

tgx = 5/7

x=arctg (5/7) + nk, k = z