Much Simpler Matrix Operations. Addition, Subtraction, and Scalar Multiplication.

Multiplying a matrix by a scalar (a single number) is a much simpler matter than multiplying a matrix by a matrix.  In the example below you just multiply each number in the matrix times 3:



Here is Matrix B:       Matrix B

   Adding two matrices only requires that they be similarly shaped.   






The same is true with subtracting matrices:






You can also combine scalar multiplication with subtraction or addition:

2B-A Bplus3A








Finally, you can test J versus almost any textbook with Matrix Algebra questions and answers.  The problems here are similar to those shown in Kelley’s Algebra, Chapter 9.  A great source for Algebra problems is Kelley’s Humongous Book of Algebra Problems.  You can also create your own problems using Deal.  Here’s how:  for a 3 x 3 matrix with numbers no greater than 10, you would use this Deal command  with 9?10.  You could make some number negative.  Then you would assign the matrix (=:) and use the shape command  (3 3 $) to make your 3 x 3 matrices.  Use J.  Play with J.


About Richard Rollo

I am a retired Community College Instructor. I taught Political Science 1 American Government for 22 years in Southern California. I am originally from Northern Minnesota. My earliest years were spent in the living quarters of a rural Duluth Winnipeg & Pacific Railway Depot. Then my family joined the great 1950's migration to Southern California where I joined up with fellow baby boomers in overcrowded schools.
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