tg^2 (x+5p)=tg^2 x sin (x-5p)=-sin x 2/ tg^2 (x)=2ctg^2 (x) 2ctg^2 (x)=2/sin^2 (x) - 2 2/sin^2 (x)-1/sin(x)-6=0 1/sin(x)=t 2t^2-t-6=0 t=2, t=-1,5 x=pi/6+2pi*n x=5pi/6+2pi*n x=arcsin(-2/3)+2pi*n x=pi-arcsin(-2/3)+2pi*n x=pi/6, arcsin(-2/3)