Question

Given that a = 2i + 4j + 3k and b = i + j – 4k, find the scalar product

Select one:

6

-6

12

-12

Answer 1

To find the scalar product of the given vectors a and b, we will multiply their corresponding components:

a ^. b = (2i + 4j + 3k) ^. (i + j - 4k) = 2 + 4 -12 = -6

Answer 2

Correct option is (b) -6

Given, \(\vec a = 2\hat i + 4\hat j+3\hat k\)

and \(b = \hat i + \hat j - 4\hat k\)

So scalar product

\(\vec a. \vec b = (2\hat i + 4\hat j+ 3\hat k)(\hat i + \hat j - 4\hat k)\)

\(= 2(1) +4(1)- 12(1)\)

\(= 2 + 4 -12\)

\(= 6 - 12\)

\(=-6\)