CAIE A Level Mathematics 9709 · Vectors

Vectors: calculation question

3 marksFoundation

Two vectors are $\mathbf{a} = 5\mathbf{i} - 4\mathbf{j} + 4\mathbf{k}$ and $\mathbf{b} = -5\mathbf{i} + 4\mathbf{j} + 5\mathbf{k}$ .

(a)
Find $|\mathbf{a} + \mathbf{b}|$ .
[3]

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