VECTORS
Example 11:
Find the direction angle of vector
.
Let's look at a picture of the vector and its direction angle. Remember that a direction angle is
positive and measured from the positive x-axis to the vector in standard position as shown
below!
Knowing that
, we can find
Looking at the graph of the vector, we know that we are required to find a positive angle whose
terminal side is in Quadrant IV.
We will use the Reference Angle of -60o which is 60o to find that the direction angle must equal
300o.
Example 12:
Find the direction angle of vector
.
Let's look at a picture of the vector and its direction angle. Remember that a direction angle is
positive and measured from the positive x-axis to the vector in standard position as shown
below!
Knowing that
, we can find
Looking at the graph of the vector, we know that we are required to find a positive angle whose
terminal side is in Quadrant IV.
We will use the Reference Angle of 30o which is 30o to find that the direction angle must equal
210o.