Question

Given a = 2î +39+ 4k, b = 3î +4j+ 5ť
find the angle between ā and b.​

Answer 1

Answer:

bhai is quetion me j 39 hai ya 3k hai, o to bata do

Answer 2

Answer:

Consider the vector

A

=2

i

^

+3

j

^

−4

k

^

And

B

=5

i

^

+2

j

^

+4

k

^

Now, as we know

A

.

B

=ABcosθ

θ is the angle between

A

and

B

Therefore,

cosθ=

AB

A

.

B

cosθ=

2

2

+3

2

+(−4)

2

5

2

+2

2

+4

2

(2

i

^

+3

j

^

−4

k

^

).(5

i

^

+2

j

^

+4

k

^

)

=

2

2

+3

2

+(−4)

2

5

2

+2

2

+4

2

(10+6−16)

=0

Therefore, cosθ=0

θ=90

∘

Hence angle between the vectors is 90

∘