Question

Find a • b if a = 3i + 8j and b= -0.5i - 4j.

A. (-1.5, -32)

B. -33.5

C. (2.5, 4)

D. -30.5

Answer 1

For this case we have the following vectors:
a = 3i + 8j
b = -0.5i - 4j
Using product point we have:
a.b = (3i + 8j). (- 0.5i - 4j)
a.b = (3) * (- 0.5) + (8) * (- 4)
a.b = -1.5 + -32
a.b = -33.5
Answer:
The point product is given by:
a.b = -33.5
B. -33.5