Vector Algebra Question 281
Question: If the points $ \mathbf{a}+\mathbf{b},\mathbf{a}-\mathbf{b} $ and $ \mathbf{a}+k,\mathbf{b} $ be collinear, then k =
Options:
A) 0
B) 2
C) 2
D) Any real number
Show Answer
Answer:
Correct Answer: D
Solution:
- $ (\mathbf{a}-\mathbf{b})-(\mathbf{a}+\mathbf{b})=[ (\mathbf{a}+k\mathbf{b})-(\mathbf{a}-\mathbf{b}) ] $
$ \Rightarrow -2\mathbf{b}=(k+1)\mathbf{b} $ . Hence $ k\in R. $
BETA
