Question

Find a.b. a=2i+j, b=i-j+k

Answer 1

A.B=1

Explanation:

A.B= AxBx+AyBy+AzBz

=(2 x 1)+(1 x -1)+(0 x 1)

= 2-1

=1

Answer 2

`a.b = 1`

Explanation:

We are given the following in the question:

`a=2i+j\\b=i-j+k`

We have to find the dot product.

Formula:

`a = x_1i + x_2j + x_3k\\b = y_1i + y_2j + y_3k\\a.b = x_1y_1 + x_2y_2 + x_3y_3`

Putting the corresponding values we get,

`a.b = (2.1) + (1.-1) + (0.1)\\= 2-1+0\\=1`

`a.b = 1`