Question

a=1 b=2 c=3 and a+b+c=0 then value of a.b+b.c+c.a is equal to vectors

Answer 1

a.b+b.c+c.a=1*2+2*3+3*1
=2+3+1
=>a+b+c =0
a. b + b. c + c. a =0