Question

find the unit vector in direction of p= 4j- 8k​

Answer 1

Answer:

We have:

3

i

+

4

j

−

k

Let

u

=

3

i

+

4

j

−

k

.

Unit vectors are of the form

ˆ

u

=

u

|

u

|

:

⇒

ˆ

u

=

3

i

+

4

j

−

k

|

3

i

+

4

j

−

k

|

⇒

ˆ

u

=

3

i

+

4

j

−

k

√

3

2

+

4

2

+

(

−

1

)

2

⇒

ˆ

u

=

3

i

+

4

j

−

k

√

9

+

16

+

1

⇒

ˆ

u

=

3

i

+

4

j

−

k

√

26

Answer 2

Answer: =>1/√80 x (4j-8k)

Explanation:

vector P = 4j - 8k

Magnitude of P = |P| = √[(4x4) + (8x8)] = √80

now, unit vector of P = P/|P|

          =>1/√80 x (4j-8k)   = answer :)