Question

Find a ⋅ b.

a = 7i - 4j, b = 4i + 3j

A) <28, -12>
B) 16
C) -40
D) <11, -1>

Answer 1

B) 16

Explanation:

The dot product of a pair of vectors is the sum of the products of their corresponding parts. It is a scalar.

... a · b = (7i -4j) · (4i +3j) = 7·4 + (-4)·3

... = 28 -12 = 16