Find a.b, a = <7, 4>, b = <3, 5>

Solution:

Let the vectors

a = 7i + 4j

b = 3i + 5j

We know that if

U = (U1)i + (U2)j

And

V = (V1)i + (v2)j

Then the dot product U.V will be:

U.V = (U1).(V1) + (U2).(V2)

Therefore

a.b = (7)(3) + (4)(5)

= 21 + 20

a.b= 41

Find a.b, a = <7, 4>, b = <3, 5>

Summary:

If a = <7, 4>, b = <3, 5>, then a.b = 41