cos^2(x/2)+sin^2(x/2)-cos^2(x/2)+sin^2(x/2)-sin(x/2)/cos(x/2)=
=2sin^2(x/2)-sin(x/2)/cos(x/2)=sin(x/2)[2sin(x/2)-1/cos(x/2)]=0
sinx/2=0
x=2Пk
sinx=1
x=П(2k+1)/2
cos^2(x/2)+sin^2(x/2)-cos^2(x/2)+sin^2(x/2)-sin(x/2)/cos(x/2)=
=2sin^2(x/2)-sin(x/2)/cos(x/2)=sin(x/2)[2sin(x/2)-1/cos(x/2)]=0
sinx/2=0
x=2Пk
sinx=1
x=П(2k+1)/2