Let a, b and c be unit vectors such that a is perpendicular to the plane containing b and c and angle between b and c is 3 . Then, | a + b + c |=

Step-by-step solution

As given a is perpendicular to b and c a b =0 and a c =0 and angle between b and c= 3 b c =| b || c | 3 =1 1 1 2 = 1 2 [ b and c are unit vectors ] Now, aligned | a + b + c |^2=| a |^2+| b |^2 & +| c |^2 & +2( a b + b c + c a ) aligned aligned & =1+1+1+2 (0+ 1 2 +0 )=1+1+1+1=4 & |a+b+c|= 4 =2 units aligned