Question

ctg^2x -8ctgx +7 =0 Найти Х

Answer 1

$ctg^2x-8ctgx+7=0 t=ctgx t^2-8t+7=0 t_{1} =7; t_{2}=1 ctgx=7; ctgx=1 x_{1}=arcctg7+ pi k,kZ x_{2}= frac{ pi }{4}+ pi k,kZ$