A unit vector making an obtuse angle with x-axis and perpendicular to the plane containing the points also makes an obtuse angle with
Let the given points be A, B and C respectively. The unit vectors perpendicular to the plane containing A, B and C are given by
Since the required vector makes an obtuse angle with x-axis.
So, it is equal to
Clearly, it also makes an obtuse angle with z-axis.
The value of x for which the angle between and is obtuse and the angle between and the z-axis is acute and less than π/6, are
If are two unit vectors such that , then the angle between , is
, then the angle between
If are unit vectors and θ is the acute angle between them, then is a unit vector for
For any vector
is equal to
A unit vector perpendicular to the plane of and is
The number of vectors of unit length perpendicular to the vectors
is a unit vector such that