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If $\vec α = 2\hat i+ 3\hat j-\hat k, \vec β=−\hat i+2\hat j−4\hat k, \vec γ =\hat i+\hat j+\hat k$, then $(\vec α × \vec β).(\vec α × \vec γ)$ is equal to |
-74 74 64 60 |
-74 |
We have, $(\vec α × \vec β).(\vec α × \vec γ)=(\vec α.\vec α)(\vec β.\vec γ)-(\vec α.\vec γ)(\vec β.\vec α)$ $⇒(\vec α × \vec β).(\vec α × \vec γ)=-3×14-8×4=-42-32=-74$ |
