onsider the vectors a→=3i→+j→−k→,b→=−3i→−j→+k→,c→=i→+0. 333333j→+0.333333k→ d→=i→+3j→+4k→,g→=i→+3j→−k→. Which pairs (if any) of these vectors are (a) Are perpendicular? (Enter none or a pair or list of pairs, e. g., if a→ is perpendicular to b→ and c→, enter (a, b),(a, c).) (b) Are parallel? (Enter none or a pair or list of pairs, e. g., if a→ 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 a→ is at an angle less than pi/2 from b→ and c→, 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 a→ is at an angle greater than pi/2 from b→ and c→, enter (a, b),(a, c).)