Find the angle between two vectors 
and 
if 
Given
.
Let the angle between vectors
and
be θ.
We know the cross product of two vectors 
and 
forming an angle θ is
where 
is a unit vector perpendicular to
and 
is a unit vector 
We also have the dot product of two vectors 
and 
forming an angle θ is
But, it is given that
⇒ sin θ = cos θ
⇒ tan θ = 1
Thus, the angle between two vectors is
.
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