If , and , then is equal…

MATHEMATICS · Single correct · IB Diploma Programme · Mathematics: Analysis and Approaches · Geometry and Trigonometry · Geometry and Trigonometry

Problem

\mathbf{a} = \hat{i} + 2\hat{j} - 2\hat{k}

\mathbf{b} = 2\hat{i} - \hat{j} + \hat{k}

and

\mathbf{c} = \hat{i} + 3\hat{j} - \hat{k}

, then

\mathbf{a} \times (\mathbf{b} \times \mathbf{c})

is equal to (1)

20\hat{i} - 3\hat{j} + 7\hat{k}

(2)

20\hat{i} - 3\hat{j} - 7\hat{k}

(3)

20\hat{i} + 3\hat{j} - 7\hat{k}

(4) None of the above