Question

In component form, vector A is 3i + 6j, and vector B is i + 2j. What is the scalar product of these vectors?

Answer 1

Answer: 15

Explanation:

Answer 2

Given,

A= (3 i + 6 j), B= (i + 2 j)

Formula of scalar or dot product is A.B

Dot product of i.i=j.j=1

and Dot product of i.j=0

A.B= (3 i+6 j) (i + 2 j)

      = (3 i.i +6 i.j +6 i.j+12 j.j)    

      = (3+0+0+12) [By the Formula , i.i= 1, j.j=1, i.j=0]

      =15      

∴The scalar product of these vectors is 15.