Question

Find the dot product, a • b.

a = 6i + 5j, b = -5i + 4j

Answer 1

are a, b vectors?

Answer 2

The answers are:
50
-10
<1, 9>
<-30, 20>
Would it be -10 or <-30, 20>? I forget if you leave it or add it together.

Answer 3

you have to multiply component times component, namely:
\[a*b=(6*-5)+(5*4)=-30+20=-10\]

Answer 4

Thanks! @Michele_Laino

Answer 5

since i*j=0, i*i=j*j=1

Answer 6

Thanks!