Question

16. Find the projection of the vector. A={-23 + k onto the direction of vector B = 41 - 4 + 7k,​

Answer 1

Answer:

Let

a

=i−2j+k and

b

=4i−4j+7k

Now

a

⋅

b

=(

i

^

−2

j

^

+

k

^

)(4

i

^

−4

j

^

+7

k

^

)

⇒

a

.

b

=4+8+7=19

Also, ∣

a

∣=

1+4+1

=

6

,∣

b

∣=

16+16+49

=

81

=9

Therefore projection of

a

on

b

is =

∣

b

∣

∣

a

⋅

b

∣

=

9

19