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Question: Answered & Verified by Expert
Let $\mathbf{a}=\hat{i}+x \hat{j}+\hat{k}, \mathbf{b}=\hat{i}+\hat{j}+\hat{k}$ and $|\mathbf{a}+\mathbf{b}|=|\mathbf{a}|+|\mathbf{b}|$, then
MathematicsVector AlgebraAP EAMCETAP EAMCET 2022 (07 Jul Shift 2)
Options:
  • A $x=1$
  • B $x=-1$
  • C $x=0$
  • D No such real $x$ exist
Solution:
1954 Upvotes Verified Answer
The correct answer is: $x=1$
$|\mathbf{a}+\mathbf{b}|=|\mathbf{a}|+|\mathbf{b}| \Rightarrow \mathbf{a}, \mathbf{b}$ are in same direction.
$$
\frac{1}{1}=\frac{x}{1}=\frac{1}{1} \Rightarrow x=1
$$

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