1-sin2x=cosx-sinx
(cosx-sinx)²-(cosx-sinx)=0
(cosx-sinx)(cosx-sinx-1)=0
cosx-sinx=0/cosx≠0
1-tgx=0⇒tgx=1⇒x=π/4+πn,n∈Z
cosx-sinx-1=0
cos²(x/2)-sin²(x/2)-2sin(x/2)cos(x/2)-sin²(x/2)-cos²(x/2)=0
2sin²(x/2)+2sin(x/2)cos(x/2)=0
2sin(x/2)(sin(x/2)-cos(x/2))=0
sin(x/2)=0⇒x/2=πk,k∈Z⇒x=2πk,k∈Z
sin(x/2)-cos(x/2)=0/cos(x/2)≠0
tg(x/2)-1=0⇒tg(x/2)=1⇒x/2=π/4+πt,t∈Z⇒x=π/2+2πt,t∈Z