math01 202.38.126.65/nankaisource/graphics 马鞍面)只有两族直母线, 所以参数曲线即直

http://202.38.126.65/nankaisource/graphics/analytic%20geometry/hyper_prra/hyper_para1.htm

http://lxy.hutc.zj.cn/baomi/special/wfjh_old/skja%5C2%5C21.pdf