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suivant: Step by step Gauss-Jordan monter: Linear systems précédent: Gauss-Jordan reduction: rref gaussjord   Table des matières   Index


Solving A*X=B : simult

simult is used to solve a linear system of equations (resp. several linear systems of equations with the same matrix A) written in matrix form (see also 1.31.17) :
A*X=b (resp A*X=B)
simult takes as arguments the matrix A of the system and the column vector (i.e. a one column matrix) b of the second member of the system (resp. the matrix B whose columns are the vectors b of the second members of the different systems).
The result is a column vector, solution of the system (resp. a matrix whose columns are the solutions of the different systems).
For example, to solve the system :

$\displaystyle \left\{\vphantom{
\begin{array}{lcr} 3x + y & = &-2 \\  3x +2y & =& 2 \end{array}}\right.$$\displaystyle \begin{array}{lcr} 3x + y & = &-2 \\  3x +2y & =& 2 \end{array}$

input :
simult([[3,1],[3,2]],[[-2],[2]])
Output :
[[-2],[4]]
Hence x = - 2 and y = 4 is the solution.
Input :
simult([[3,1],[3,2]],[[-2,1],[2,2]])
Output :
[[-2,0],[4,1]]
Hence x = - 2 and y = 4 is the solution of

$\displaystyle \left\{\vphantom{
\begin{array}{lcr} 3x + y & = &-2 \\  3x +2y & =& 2 \end{array}}\right.$$\displaystyle \begin{array}{lcr} 3x + y & = &-2 \\  3x +2y & =& 2 \end{array}$

whereas x = 0 and y = 1 is the solution of

$\displaystyle \left\{\vphantom{
\begin{array}{lcr} 3x + y & = &1 \\  3x +2y & =& 2 \end{array}}\right.$$\displaystyle \begin{array}{lcr} 3x + y & = &1 \\  3x +2y & =& 2 \end{array}$


next up previous contents index
suivant: Step by step Gauss-Jordan monter: Linear systems précédent: Gauss-Jordan reduction: rref gaussjord   Table des matières   Index
giac documentation written by Renée De Graeve and Bernard Parisse