Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Search any question & find its solution
Question: Answered & Verified by Expert
Let D is a point on the line l1:x+y-2=0S3,3 is a fixed point and line l2 is the perpendicular to DS and passing through S. If MK is another point on the line l1 (other than D), then the locus of the point of intersection of l2 and angle bisector of the angle MDS is a conic whose length of latus rectus rectum is equal to
MathematicsParabolaJEE Main
Options:
  • A 42
  • B 4
  • C 8
  • D 22
Solution:
1873 Upvotes Verified Answer
The correct answer is: 42

Let the point of intersection of l2 and angle bisector of the angle MDS is Ph,k.

Draw perpendicular PF to l1 from P.

Now, ΔPFD and ΔPSD are congruent triangles.

Hence, PF=PS

locus of P is a parabola having S as focus and l1 as the directrix
Hence, the length of the latus rectum is 23+3-21+1=42 units
 

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.