linear equations with indexed variables?
- To: mathgroup at smc.vnet.net
- Subject: [mg6896] linear equations with indexed variables?
- From: hxie at gradin.cis.upenn.edu (Hong-liang Xie)
- Date: Fri, 25 Apr 1997 14:00:30 -0400 (EDT)
- Organization: University of Pennsylvania
- Sender: owner-wri-mathgroup at wolfram.com
I am new to Mathematica and I need to solve a system of linear equations whose variables are indexed (i.e., x, x, x), for example, 3x[i] = 2x[i+1] + x[i-1] ( 1 <= i <= 3) x[4 ] = 1 x = 0 The above is a system of 5 linear equations with 5 variables x, x, x, x, x. I can certainly rewrite it into 5 equations using 5 variables x0, x1, x2, x3, x4. However, if the range of i gets bigger, or, worse, if each x has two indexes as in x[i,j], this rewriting could get of hand quickly. I tried different equation solving functions in Mathematica but with no luck. I would therefore appreciate help from experts here on how to solve this kind of equations directly. Thanks a lot! Hong CIS Dept Univ of Pennsylvania