Linear System (System of linear equations)

It’s a collection of one ore more linear equations involving the same variables, like:

A system could be:

  • Determinated if there are the same number of equation unknowns
  • Overdeterminated if there are more equation that the number of unknowns
  • Underdeterminated if the number of equation is fewer than the number of unknowns

Solutions

A solution to a linear system is an assignement of values is an assignement to variables such that all the equations are simultaneously satisfied.

Example of solution in a linear system with two equations: LinearSystemSolutions

General Form

A general system of m linear equations with n unknown and coefficients can be written as:

Which can be written in vectoral or matrix form.

Homogeneous Equations

A system of equations is called homogeneous if all the costant terms are zero:

The solution is called trivial solution. Any solution with atleast a non zero is called nontrivial solution.

Matrix equation

The general form can be seen as a matrix equation: , with the matrix A being of size representing coefficients, and the vector b are the solutions.


Sources