∵tanπ/3=√3、π∴∠A=π+π/3∴sinA=sin(π+π/3) =-sin(π/3) =-√3/2 cosA=cos(π+π/3) =-cos(π/3) =-1/2∴sinA-cosA =-√3/2+1/2 =(1-√3)/2
