y=(1-sinx)/(2-cosx)>0 y=sina/cosa>0 y^2=(sina/cosa)^2=(1-cos^2a)/cos^2a cos^2a=1/(1+y^2) 1/cosa=±√(1+y^2) 2y-ycosx=1-sinx 2y-1=ycosx-sinx=(sina/cosa)*cosx-sinx=sin(a-x)/cosa 2y-1=[±√(1+y^2)]*sin(a...