Explain how we can read column vectors

A column vector is written vertically, with each element stacked one below the other.
For example:

v = [ 1 ]
    [ 5 ]
    [ 9 ]

You read the elements starting from the top and moving downwards.

• The first element (topmost) is the first component.
• The second element is the second component.
• And so on, until the last element (bottommost).

In mathematical notation, elements are often indexed with a subscript indicating their position. For a column vector v, v_1 would be the first element, v_2 the second, and so forth.
In the example above:

• v_1 = 1
• v_2 = 5
• v_3 = 9

The meaning of each component depends on the context. For instance, in 3D space, a column vector [x; y; z] would represent a point or a direction, where x is the first component, y the second, and z the third.