If  are Two Unit Vectors Such That , Then The Angle Between , Is 

Let  be vectors of equal magnitude such that the angle between  Then, the minimum value of the cos α + cos β + cos γ is

Let  be three vectors of equal magnitude such that the angle between each pair is  If   

If , then the value of  is equal to

Angle between vectors  are unit vectors satisfying 

The values of ‘a’ for which the points A, B, C with position vectors  respectively are the vertices of a right angled triangle with C = π/2 are 

The vectors  are the adjacent sides of a parallelogram. Then, the acute angle between its diagonals is

If  are two vectors such that  then angle between 

The values of x for which the angle between the vectors  is acute, and the angle between the vector  and the axis of ordinates is obtuse, are

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  

, then the angle between