二元函数沿某一方向的泰勒展开式

Taylor Expansion of Two Variable Functions along a Direction

给出二元函数高阶方向导数的定义与计算公式,给出并证明二元函数在方向导数意义下的泰勒展开式,由此引出方向曲率概念.

This paper presents the definition and computational formula of higher order directional derivative and the Taylor expansion of two variable functions along a direction. The computational formula of directional curvature is also given.