测试LaTex x2+y2−xy−1=0 x^2+y^2-xy-1=0 x2+y2−xy−1=0 因为 (x−y2)2+(3y2)2=1 (x-\frac{y}{2})^2+(\frac{\sqrt{3}y}{2})^2=1 (x−2y)2+(2