If vector(a) = i - j +7k and vector(b) = 5i - j + λk then find the value of λ,

Question

If \(\vec{a}=\hat{i}-\hat{j}+7\hat{k}\) and \(\vec{b}=5\hat{i}-\hat{j}+\lambda\hat{k}\) then find the value of λ, so that \(\vec{a}+\vec{b}\) and \(\vec{a}-\vec{b}\) are perpendicular vectors.

Answer 1

\((\vec{a} + \vec{b})\) is perpendicular to \((\vec{a} - \vec{b})\)