Matrix-simple problem

1. Nov 30, 2005

chandran

|F1| |K11 K12 K13| |U1|
|F2| = |K21 K22 K23| * |U2|
|F3| |K31 K32 K33| |U3|

I have the above matrix relating F K AND U .

In this F & k are known but u is unknown

Suppose i know U(i) is equal to 0 can i eliminate the ith row and jth column of the K matrix and solve the remaining. How this can be understood.

2. Nov 30, 2005

Tide

You can understand it this way. Your matrix system represents a set of n linear equations in n unknowns. If the value of one of the unknowns is "discovered" then you need only n-1 equations to resolve the remaining unknowns. Obviously, the column corresponding to the resolved value can be eliminated if the value is 0. You get to pick which of the two remaining equations to keep.