How lucky my sister was for waking me up at the middle at the night to teach her the simplex method, in the matrix way for her exam in a few hours. How luckier I am, it is one of the class topics we were about to discuss allowing me to recall on some things.
Here is a simple maximization problem from her book. All we needed to do after the first table is to make the $2$ x $2$ matrix on the upper left an identity matrix and the last $1$ x $2$ matrix on the lower left, zeroes. Remember that these are equations so the "elimination via matrix" is applied.
Minimization
For minimization problems, a little tweaking is needed. Example, if you are given
\[ \text{min } z = 0.15x_1+0.12x_2\]
with constraints
\[ \begin{split} 60x_1 +60x_2 & \geq 300 \\ 12x_1 + 6x_2 & \geq 36 \\ 10x_1 + 30x_2 & \geq 90 \end{split} \]
then we have the matrix
\[ \begin{bmatrix} 60 & 60 & \vdots & 300 \\ 12 & 6 & \vdots & 36 \\ 10 & 30 & \vdots & 90 \\ \cdots &\cdots & \vdots & \cdots \\ 0.15 & 0.12 & \vdots & 0\\ \end{bmatrix} \]
The transpose of this matrix will give you a maximization problem and the rest of the process is the same as earlier.
Application - Simplex method Application varies from business to business and are commonly used.
Links for more info is provided below:
http://pages.intnet.mu/cueboy/education/notes/algebra/simplex.htm
http://college.cengage.com/mathematics/larson/elementary_linear/5e/students/ch08-10/chap_9_3.pdf
http://college.cengage.com/mathematics/larson/elementary_linear/5e/students/ch08-10/chap_9_4.pdf
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