What do you suppose is the length of the vector represented by:

(3, 0)T

A good answer might be:

It seems plausible that the length is 3 units.

Vectors Aligned with X-Y Axes


When a 2D vector is aligned with the x axis, the column matrix that represents it has a non-zero value in the first element, and zero for the second element.

The green vector is represented by: (3, 0)T. It is easy to determine its length — the length is the value of the single non-zero element.

Vector a (the blue vector in the diagram) is aligned with the y axis. Its matrix is (0,4)T.


What is the length of a?