Vector Algebra Question 219
Question: If $ \mathbf{a}=2\mathbf{i}+\mathbf{j}-8\mathbf{k} $ and $ \mathbf{b}=\mathbf{i}+3\mathbf{j}-4\mathbf{k}, $ then the magnitude of $ \mathbf{a}+\mathbf{b}= $
[MP PET 1996]
Options:
A) 13
B) $ \frac{13}{3} $
C) $ \frac{3}{13} $
D) $ \frac{4}{13} $
Show Answer
Answer:
Correct Answer: A
Solution:
- $ |\mathbf{a}+\mathbf{b}|,=,|3\mathbf{i}+4\mathbf{j}-12\mathbf{k}|,=,|\sqrt{3^{2}+4^{2}+12^{2}}|,=13 $
$ \therefore ,\mathbf{a}+\mathbf{b}=13 $ .
BETA
