Talk:High School Mathematics Extensions/Matrices

Introducing Terms
In "Matrix multiplication", 2nd paragraph, the term vector is introduced. This might cause confusion to readers new to matrices, as the definition follows after the exaples ("A matrix with just one row is called a row vector [...]"). Probably a better place to introduce the term is above, in "Introduction", where you have an example of a 1 x 6 matrix. In this context I'd also suggest the addition of an m x 1 vector to point out, that vectors are not just of the form 1 x n.

After the examples in "Multiplication of non-vector matrices" you add the note: "Multiplication of matrices is generally not commutative, i.e. generally AB ≠ BA.". I consider this to be too late; already the first two examples in "Matrix Multiplication, Exercices" have tho multiplications with reversed factors.

I didn't edit right away, as you maybe followed your approach intentionally for didactic reasons.

Gulliveig 17:05, 8 January 2007 (UTC)

Square matrix required
should mention that a matrix must be square to have be inverted and compute a determinant....--Billymac00 (talk) 01:04, 13 March 2008 (UTC)

Newton-Leibniz
Maybe the comment introducing Leibniz as Newton's greatest rival should be removed as historically imprecise and because it put these two great mathematicians in a questionable light. It is not mentioned in Wikipedia pages, and I have no source available at the moment, but my understanding is that Nweton and Leibnitz were not (at least initially) personally very active in the "Newton-Leibniz rivalry", which was mainly a rivalry between their countrymates.

Matrix Multiplication
At Matrix Multiplication The first example is a 2x1 matrix being multiplied by a 1x2 matrix which yielded a 1x1 matrix [as indicated in the Note]. Further down at Multiplying non-vector matrices it is indicated at Ex.No.4 a 2x1 matrix multiplied by a 1x2 matrix is a 2x2 matrix. There appears to be some confusion or conflict that requires explanation.