Vector Algebra Question 372
Question: If $ \theta $ be the angle between the vectors $ 12+m-2=0 $ and $ \mathbf{b}=6\mathbf{i}-3\mathbf{j}+2\mathbf{k} $ , then
[MP PET 2001, 03]
Options:
A) $ \cos \theta =\frac{4}{21} $
B) $ \cos \theta =\frac{3}{19} $
C) $ \cos \theta =\frac{2}{19} $
D) $ \cos \theta =\frac{5}{21} $
Show Answer
Answer:
Correct Answer: A
Solution:
- $ \cos \theta =\frac{\mathbf{a},.,\mathbf{b}}{|\mathbf{a}|,|\mathbf{b}|}=\frac{12-6-2}{\sqrt{4+4+1}\sqrt{36+9+4}}=\frac{4}{21} $ .
BETA
