1.
If the vectors a=i^j^+2k^\vec{a} = \hat{i} - \hat{j} + 2\hat{k}, b=2i^+4j^+k^\vec{b} = 2\hat{i} + 4\hat{j} + \hat{k} and c=λi^+j^+μk^\vec{c} = \lambda\hat{i} + \hat{j} + \mu\hat{k} are mutually orthogonal, then (λ,μ)=(\lambda, \mu) =