Vector Algebra Question 246
Question: Angle between the line $ \mathbf{r}=(2\mathbf{i}-\mathbf{j}+\mathbf{k})+\lambda (-\mathbf{i}+\mathbf{j}+\mathbf{k}) $ and the plane $ \mathbf{r}.(3\mathbf{i}+2\mathbf{j}-\mathbf{k})=4 $ is
Options:
A) $ {{\cos }^{-1}}( \frac{2}{\sqrt{42}} ) $
B) $ {{\cos }^{-1}}( \frac{-2}{\sqrt{42}} ) $
C) $ {{\sin }^{-1}}( \frac{2}{\sqrt{42}} ) $
D) $ {{\sin }^{-1}}( \frac{-2}{\sqrt{42}} ) $
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Answer:
Correct Answer: D
Solution:
- Use the formula, $ \cos \theta =\frac{\mathbf{n}.\mathbf{b}}{|\mathbf{n}||\mathbf{b}|} $ .
BETA
