Question

Find the angle between the vectors: A = i-2j-5k and B= 2i+j-4k.

Answer 1

Explanation:

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Answer 2

Answer:

A = i - 2j - 5k

B = 2i + j - 4k

now, we know that

A.B = |A||B|Sinθ

or

( i - 2j - 5k).( 2i + j - 4k) = (12 + 22 + 52)1/2.(22 + 12 + 42)1/2 Sinθ

or

2 - 2 + 20 = 5.477 x 4.582 Sinθ

thus, the angle between the two vectors will be given as

Sinθ = 20 / 25.0956

or

θ = sin-1 (0.7969)

thus,

θ = 52.835°