If the points A and B are (1, 2, -1), and (2, 1, -1) respectively… - Vidyadip

MCQ

If the points $A$ and $B$ are $(1, 2, -1),$ and $(2, 1, -1)$ respectively, then $ \vec{ \text{AB }} $ is:

A
$\hat{\text{i}}+\hat{\text{j}}$
✓
$\hat{\text{i}}-\hat{\text{j}}$
C
$2\hat{\text{i}}+\hat{\text{j}}-\hat{\text{k}}$
D
$\hat{\text{i}}+\hat{\text{j}}+\hat{\text{k}}$

✓

Answer

Correct option: B.

$\hat{\text{i}}-\hat{\text{j}}$

$ \vec{ \text{AB}}=\langle{2-1, 1-2,-1+1}\rangle$
$=\langle{1, -1, 0}\rangle$
$\therefore \vec{ \text{AB}}=\hat{\text{i}}-\hat{\text{j}}$

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