2sinx-3cosx=0 и cosx+sinx=cos2x заранее спасибо

2sinx-3cosx=0 tg(x)=3/2 x=artg(3/2) x=56.03 градуса cos(x)+sin(x)=2cos(2x) cos(x)+sin(x)=cos^2(x)-sin^2(x) cos(x)+sin(x)=(cos(x)-sin(x))(cos(x)+sin(x)) (cos(x)-sin(x)-1)(cos(x)+sin(x)=0 cos(x)+sin(x)=0 tg(x)=-1 x=-п/4+2пк cos(x)-sin(x)-1=0 cos^2(x)=1+2sin(x)+sin^2(x) 1-sin^2(x)=1+2sin(x)+sin^2(x) 2sin(x)+2sin^2(x)=0 2sin(x)(1+sin(x))=0 sin(x)=0 x=0+2пк 1+sin(x)=0 sin(x)=-1 x=-п/2+2пк