MAI391_-_Pactice_-_Questions_191.webp

Let x, y ∈ R2. The cosine of the angle between T T vectors [10] and [1 -1] by using the inner product \langle x,y\rangle=x^{T}[\begin{matrix}2&-1\\ -1&2\end{matrix}]y. is
(i) \sqrt{3}/2
(ii) \sqrt{2}/2
(iii) 1/2
(iv) 1