The-vector-a-3i-2j-2k-and-b-i-2k-are-the-adjacent-sides-of-a-parallelogram-Then-angle-between-its-diagonal-is-

Question Number 91496 by Zainal Arifin last updated on 01/May/20

The vector a = 3 i - 2 j + 2 k and b = - i - 2 k

are the adjacent sides of a parallelogram .

Then angle between its diagonal is

Commented by jagoll last updated on 01/May/20

\vec{a} + \vec{b} = (2, - 2, 0)

\vec{a} - \vec{b} = (4, - 2, 4)

l e t θ = t h e a n g l e b e t w e e n d i a g o n a l s

\cos θ = \frac{8 + 4}{2 \sqrt{2} . 6} = \frac{1}{\sqrt{2}} \Rightarrow θ = \frac{π}{4}

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