Complex sentence: The geometric meaning is solely determined by the middle matrix, please refer the geometric meaning of a quadratic form, it is easy to find out when it is an ellipse, a parabola, or a hyperbola.
Split into simpler sentences: The geometric meaning is solely determined by the middle matrix. From this, and refer to the geometric meaning of a quadratic form, it is easy to find out when it is an ellipse, a parabola, or a hyperbola.