Coordinate vectors should ALWAYS be columns

Always always always always always always.

The definition of matrix multiplication requires that you go across the rows of the matrix on the left and go down the columns of the matrix on the right.

For a matrix to represent a linear transformation, it should act on the left of a vector. Therefore, the vector has to be written as a column.

Linear algebra texts that use row vectors, and especially those that switch between using row and column vectors, should be destroyed.

1 comment:

Scott the Hobo said...

This is truly one of my greatest pet peeves.