Most Important Selected Qs for JEE AdvancedMathematicsParabola
If two distinct chords of a parabola x^2=4 ay passing through (2 a, a) are bisected on the line x+y=1 , then length of latus rectum can be -
Options
- A2
- B1
- C4
- D5
Correct answer
B. 1
Step-by-step solution
Any point on the line x+y=1 can be taken as ( , 1- ) so equation of the chord taking this point as mid point will be x-2(y+1- )= ^2-4 a(1- ) It passes through (2 a, a) aligned & 2 a -2 a ( a +1- )= ^2-4 a (1- ) & ^2-2 a +2 a ^2=0 aligned It has two distinct root then aligned & - (-2 a +2 a ^2 ) 0 & a ^2- a 0 0 a 1 aligned length of latus rectum can be between 0 and 4 .