若0若0
若0|sinA+cos^2A-1|/√sin^A+cos^A=1/4|sinA-sin^2A|=1/4又0≤A≤π/2所以sinA≥sin^2A所以有sinA-sin^2A=1/4sin^2A-sinA+1/4=0(sinA-1/2)^2=0sinA=1/2cosA=√3/2L的斜率=-sinA/cosA=-1/2/(√3/2)=-√3/3