201.

Let  Find a vector  which is perpendicular to both 

Let  Find a vector  which is perpendicular to both  and 

If  show that the angle  between the vectors  is given by

If  show that the angle between  is 60°.

Let  be three vectors of magnitude 5, 3, 1 respectively. If each one is perpendicular to the sum of other two vectors, prove that 

If  are three mutually perpendicular vectors of equal magnitude find the angle between 

If  are mutually perpendicular vectors of equal magnitude, show that they are equally inclined to the vector