Three edges of unit cube through origin O represent the vectors i, j, k respectively. Write down the expression for the vector represented by 

1. The diagonal of cube through O. 
2. The diagonals of three faces passing through O.

Solution:

Three edges of unit cube through origin O represent the vectors i, j, k respectively. Write down the expression for the vector represented by (i) The diagonal of cube through O. (ii) The diagonals of three faces passing through O.