1.
Shortest distance between r=3i^+5j^+7k^+λ(i^+2j^+k^)\vec{r}=3\hat{i}+5\hat{j}+7\hat{k}+\lambda(\hat{i}+2\hat{j}+\hat{k}) and r=i^j^k^+μ(7i^6j^+k^)\vec{r}=-\hat{i}-\hat{j}-\hat{k}+\mu(7\hat{i}-6\hat{j}+\hat{k}) is