Consider the vectors Which pairs (if any) of these vectors are (a) Are perpendicular? 6=-i-3j+k, d=3i- j+ k, g = = i +3j. à = 3i+j-k, c = i +3j - k (Enter none or a pair or list of pairs, e.g., if á is perpendicular to band c, enter (a,b),(a,c).) (b) Are parallel? (Enter none or a pair or list of pairs, e.g., if à is parallel to b and c, enter (a,b),(a,c).) (c) Have an angles less than π/2 between them? (Enter none or a pair or list of pairs, e.g., if à is at an angle less than pi/2 from band è, enter (a,b),(a,c).) (d) Have an angle of more than π/2 between them? (Enter none or a pair or list of pairs, e.g., if à is at an angle greater than pi/2 from b and c, enter (a,b),(a,c).)