切割函数为常值的曲线的一个结果  

A Result of Curve with Tangent and Secant Function as Constant

作　　者：岳崇山[1,2] 宋旭华[3] 

机构地区：[1]首都师范大学数学系,北京100000 [2]河北北方学院理学院,河北张家口075000 [3]宣化科技职业学院数学系,河北宣化075100

出　　处：《河北北方学院学报（自然科学版）》2010年第3期13-15,共3页Journal of Hebei North University:Natural Science Edition

摘　　要：平面闭曲线的双切圆问题在平面区域的外形识别中占据重要的地位.切割函数在双切圆的研究中起着重要的作用.重新定义了平面曲线和空间曲线的拓广的切割函数,利用微分几何技术,研究了平面曲线的拓广的切割函数恒为常值的情形,得到了一个充分必要条件,进而得到了空间曲线的拓广的切割函数恒为常值的充分条件.The question of bitangent circle of closed plane curve is very important to shape regintion about plane area, and the tangent and secant function is also important to the research of bitangent circle. By using the differential geometry technique, extended tangent and secant funcitons of plane curve and space curve are redefined, the situation of the extended tangent and secant function of curve being constant is studied and a necessary and sufficient condition is obtained. At last, a sufficient condition of the extended tangent and secant function of space curve as constant is obtained.

关 键 词：曲线 双切圆 切割函数 

分 类 号：O187.1[理学—数学]