If a⃗ = 3î - 2ĵ + k̂ and b⃗ = 2î - 4ĵ - 3k̂ then the value of |a⃗ - 2b⃗| will be:

If $\vec{a} = 3\hat{i} - 2\hat{j} + \hat{k}$ and $\vec{b} = 2\hat{i} - 4\hat{j} - 3\hat{k}$ then the value of $|\vec{a} - 2\vec{b}|$ will be:

(a)$\sqrt{85}$
(b)$\sqrt{86}$
(c)$\sqrt{87}$
(d)$\sqrt{88}$

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Answer

Correct option: (b)

Answer: (b) $\sqrt{86}$ $\vec a - 2\vec b = (3-4)\hat i + (-2+8)\hat j + (1+6)\hat k = -\hat i + 6\hat j + 7\hat k$ $|\vec a - 2\vec b| = \sqrt{1 + 36 + 49} = \sqrt{86}$