High number_ Vector algebra_ Unit vector_ Angle between vector and coordinate axis

One Unit vector

If the vector α The mold for 1,  namely |α| =1,  said α by Unit vector . 

If α≠ 0, remember  , α ⁰ be called α Of Unit vector , Its length is 1,  And there are   α = |α| α ⁰

Two   The angle between the vector and the coordinate axis

The three coordinates of the unit vector are the cosine of the direction angle of the vector .

Let's first look at an example of the properties of a theorem

Then look at an example of application

  Look at another topic

Let the direction cosine of the vector satisfy ： (1) cosa = 0;  (2) cosβ = 1;  (3) cosa = 0, cosβ = 0. Ask how these vectors relate to the coordinate axis ？

Explain ：