Question

решить уравнение
14cos^2х +sin2х=6

Answer 1

14cos^2x+sin2x=6
14cos^2x+2sinxcosx-6cos^2-6sin^2=0 |:cos^2x
6tg^2-2tgx-8=0
замена:
tgx=y
y^2-2y-8=0 |:2
y^2-y-4=0
D=1^2-4*1*(-8)=1+48=√49(7)
y1,2=1±7/6
y1=-1
y2=4/3
y1=>tg=-1 =>-pi/4+pik,k€z
y2=>tg=4/3=>arctg4/3+pik,k€z
Не?