Straight Line Question 39

Question: The points $ (at_1^{2},2at_1),(at_2^{2},2at_2) $ and $ (a,0) $ will be collinear, if

Options:

A) $ t_1t_2=1 $

B) $ t_1t_2=-1 $

C) $ t_1+t_2=1 $

D) $ t_1+t_2=-1 $

Show Answer

Answer:

Correct Answer: B

Solution:

  • $ \frac{a-at_2^{2}}{at_2^{2}-at_1^{2}}=\frac{-2at_2}{2at_2-2at_1} $
    Þ $ (1-t_2^{2})=-t_2(t_2+t_1) $ or $ t_1t_2=-1 $ .