(y+x-1)/x=(2+cosθ+1+sinθ+1-1)/(2+cosθ)=1+sinθ/(2+cosθ)
sinθ/(2+cosθ)=m
sinθ-mcosθ=2m
tga=m
cosa=1/√(1+m^2)
sinθ-mcosθ=sin(θ-a)/√(1+m^2)=2m
1≥2m*√(1+m^2)≥－1
√(-0.5+0.5√2)≥m≥-√(-0.5+√2)
1+√(-0.5+0.5√2)≥(y+x-1)/x≥1-√(-0.5+√2)