Coordinate Geometry Question 152
Question: Three points $ (p+1,1) $ , $ (2p+1,3 $ ) and $ (2p+2,\ 2p) $ are collinear, if p =
[MP PET 1986]
Options:
A) - 1
B) 1
C) 2
D) 0
Show Answer
Answer:
Correct Answer: C
Solution:
$ \begin{vmatrix} p+1 & 1 & 1 \\ 2p+1 & 3 & 1 \\ 2p+2 & 2p & 1 \\ \end{vmatrix} =0 $
$ \Rightarrow (p+1)(3-2p)+1(2p+2-2p-1) $
$ +1[(2p)(2p+1)-3(2p+2)]=0 $
$ \Rightarrow p=2 $ .
BETA
