Question-126567

Question Number 126567 by sdfg last updated on 21/Dec/20

Answered by physicstutes last updated on 22/Dec/20

A = (k, k) and B = (- 3, 4)

A . B = ∣ A ∣∣ B ∣ \cos θ

\Rightarrow - 3 k + 4 k = k

\Rightarrow k = \sqrt{k^{2} + k^{2}} . \sqrt{{(- 3)}^{2} + 4^{2}} \cos θ

k = 5 \sqrt{2} k \cos θ

or \cos θ = \frac{1}{5 \sqrt{2}} \Rightarrow θ = 360 ° n \pm 81.9 °, n \in Z