JEE Main & Advanced
Mathematics
Three Dimensional Geometry
Question Bank
Critical Thinking
question_answer
If the straight lines \[x=1+s,\] \[y=-3-\lambda s,\] \[z=1+\lambda s\] and \[x=t/2,y=1+t,z=2-t\], with parameters s and \[t\] respectively, are co-planar, then \[\lambda \]equals [AIEEE 2004]
A)0
B)-1
C)-1/2
D)-2
Correct Answer:
D
Solution :
We have, \[\frac{x-1}{1}=\frac{y+3}{-\lambda }=\frac{z-1}{\lambda }=s\]
and \[\frac{x-0}{1/2}=\frac{y-1}{1}=\frac{z-2}{-1}=t\]