Find the value of kkk such that ⟨1,2⟩\langle 1, 2 \rangle⟨1,2⟩ and ⟨2,k⟩\langle 2, k \rangle⟨2,k⟩ are orthogonal.
k=−1k = -1k=−1
k=−2k = -2k=−2
k=1k = 1k=1
k=2k = 2k=2