1.
If a⃗=13(3i^+k^)\vec{a} = \frac{1}{\sqrt{3}}(3\hat{i} + \hat{k}) and b⃗=17(2i^+3j^−6k^)\vec{b} = \frac{1}{7}(2\hat{i} + 3\hat{j} - 6\hat{k}), then the value of (2a⃗−b⃗)⋅[(a⃗×b⃗)×(a⃗+2b⃗)](2\vec{a} - \vec{b})\cdot[(\vec{a} \times \vec{b}) \times (\vec{a} + 2\vec{b})] is