The orthogonal projection of a vector
onto another vector
is a vector that has a magnitude equal to
and direction equal to the direction of
. Another way to think of an orthogonal projection is that it is the vector that would represent the "shadow" that
casts onto
if a light were held directly above and at a
degree angle to
.
We already know how to find the magnitude of this vector by finding
so we simply need to rescale
by this magnitude. Thus, we normalize
and multiply by
:
Excercise 2-7. Find the component of vector
along the direction of vector
. After finding this component, find the orthogonal projection of
onto
.
The component
can be found by applying the definition of vector components:
This is the magnitude of the vector
that lies along the direction of
. In order to find the orthogonal projection we simply need to multiply the unit vector
by 5: