parabola 椭圆:ellipse 退化的:degenerate 非退化的:nondegenerate 任意的:arbitrarily 相容 的:consistent 在几何上:geometrically 二次方程:quadratic equation 判别 式:discriminant 行列式:determinant 3.(1)In the planar rectangular coordinate system, one can set up a one-to-one correspondence between ...