华南理工大学学报(自然科学版) ›› 2003, Vol. 31 ›› Issue (11): 85-87.

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一类多元线性函数方程(Ⅰ)

黄新耀   

  1. 华南理工大学 应用数学系‚广东 广州510640
  • 出版日期:2003-11-20 发布日期:2022-06-17
  • 作者简介:黄新耀(1953-)‚男‚副教授‚主要从事模糊系统和函数方程研究.

On a Class of Linear Functional Equations for Functions of Several Variables (Ⅰ)

Huang Xin-yao   

  1. Department of Applied Mathematics‚South China University of Technology‚Guangzhou510640‚China
  • Online:2003-11-20 Published:2022-06-17
  • About author:Huang Xin-yao (Born in1953)‚male‚associate professor‚mainly researches on fuzzy system and functional equations.

摘要: 设函数 f(x1‚x2‚…‚xn) 对 xn 有连续二阶偏导数‚我们寻求函数方程 ∑ n i=1 (-1) i-1[ f(x1‚…‚xi + xi+1‚…‚xn+1)+ f(x1‚…‚xi - xi+1‚…‚xn+1)]+(-1) n2f(x1‚x2‚…‚xn) =0 的一般解.首先‚给出了方程∑ n i=1 (-1) i-1[ F(x1‚…‚xi + xi+1‚…‚xn+1)+ F(x1‚…‚xi - xi+1‚…‚xn+1)] =0 的一般解‚其次‚上述第1式对 xn+1两次微分‚并简化得到形如第2式的方程.第1个函数方程的一般解为 f(x1‚x2‚…‚xn) = ∑ n-1 i=1 (-1) i-1[ A(x1‚…‚xi + xi+1‚…‚xn)+ A(x1‚…‚xi - xi+1‚…‚xn)]+ (-1) n-12A(x1‚x2‚…‚xn-1). 其中 A(x1‚x2‚…‚xn-1) 是对 xn-1具有连续二阶导数的任意函数

关键词: 函数方程;可微解;偏导数 

Abstract: By letting the function f(x1‚x2‚…‚xn)have continuous partial derivatives of second order with respect to xn‚the functional equation ∑ n i=1 (-1) i-1[ f ( x1‚…‚xi + xi+1‚…‚x n+1)+ f ( x1‚…‚xi - xi+1‚…‚x n+1)] + (-1) n2f ( x1‚x2‚…‚ x n) =0is considered.First‚the general solution of the equation ∑ n i=1 (-1) i-1[ F( x1‚…‚xi + xi+1‚…‚x n+1)+ F( x1‚…‚xi - xi+1‚…‚x n+1)] =0 was presented.Then‚the first functional equation was twice differentiated with respect to xn+1 and reduced to an equation of the aforementioned type.It is found that the general solution of the first functional equation is f ( x1‚x2‚…‚x n) = ∑ n-1 i=1 (-1) i-1[ A( x1‚…‚xi + xi+1‚…‚x n)+ A ( x1‚…‚xi - xi+1‚…‚x n)] + (-1) n-12A ( x1‚x2‚…‚x n-1) . Where A(x1‚x2‚… xn-1)is an arbitrary twice continuous differentiable with respect to xn-1.

Key words: functional equation, differentiable solution, partial derivative

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