question_answer

a, b, c   are three vectors, such that \[a+b+c=0,\,\,\left| a \right|=1,\,\,\left| b \right|=2,\,\,\left| c \right|=3\], then \[a\,.\,b+b\,.\,\,c+c\,.\,\,a\] is equal to     AIEEE  Solved  Paper-2003

A)                         0                             

B) -7                           

C) 7                             

D) 1

Correct Answer: B

Solution :

Given,  also