[" 15If a,b and "c" are unit vectors,then "|a-b|^(2)+|b-c|^(2)+|c-a|^(2)" does "n],[[" a."4," b."9],[c*8," d."6]]

If a,b and c are unit vectors, then the maximum value of |a-b|^(2)+|b-c|^(2)+|c-a|^(2) is?

If a, b and c are unit vectors satisfying |a-b|^(2)+|b-c|^(2)+|c-a|^(2)=9 , then |2a+5b+5x| is

If a, b and c are unit coplanar vectors, then [[2a-b, 2b-c, 2c-a]] is equal to

If widehat a,hat b, and hat c are unit vectors,then |widehat a-hat b|^(2)+|hat b-hat c|^(2)+|hat c-widehat a|^(2) does not exceed

If vec a, vec b, vec c are unit vectors then |vec a - vec b|^(2) + |vec b - vec c|^(2) + |vec c - vec a|^(2) does not exceed.