Question

Find a ⋅ b.

a = 1i - 3j, b = 2i + 3j

Answer 1

Consider the given vectors.

a=3i+2j−6k

b=4i−3j+k

Now,

a⋅b=(3i+2j−6k)(4i−3j+k)

a⋅b=12−6−6=0

Therefore,

Two vectors a and b are perpendicular.

Thus, the angle between the vectors a and b =90

∘

Hence, this is the answer.