Question

please answer within 15mins it's urgent and time for school....

Answer 1

HAPPY FRIENDSHIP DAY TO ALL MY FRIENDS.
The solution is provided below :-

Answer 2

Hey there !

Thanks for the question !

Solution:

So Since the question asks for Vector A . Vector B, we use Dot product to calculate the product.

Vector A . Vector B = Magnitude of Vector A . Magnitude of Vector B . CosФ

But since we dont know Cos Ф, we simple multiply terms inside.

=> A.B = ( 2i + 4j + 5k ) . ( i + 3j + 6k )

=> A.B = 2i ( i + 3j + 6k ) + 4j ( i + 3j + 6k ) + 5k ( i + 3j + 6k )

We know that,

i . i = j . j = k . k = 1

i . j = j . k = k . i = 0

So applying this rule we get,

=> ( 2i . i + 2i . 3j + 2i . 6k ) + ( i . 4j + 4j . 3j + 4j . 6k ) + ( 5k . i + 5k . 3j + 5k . 6k )

=> ( 2 ( 1 ) + 0 + 0 ) + ( 0 + 12 ( 1 ) + 0 ) + ( 0 + 0 + 30 ( 1 ) )

=> 2 + 12 + 30

=> 42

Hence the dot product of Vector A and Vector B is 42.

Hope my answer helped !