A line y=mx+1 intersects the circle (x−3)2+(y+2)2=25 at the points P and Q. If the midpoint of the line segment PQ has x-coordinate −53, then which one of the following options is correct?
(A)6≤m<8
(B)2≤m<4✓ Correct
(C)4≤m<6
(D)−3≤m<−1
Answer: (B)
Solution
The midpoint R of chord PQ has coordinates (−53,5−3m+1).
Since CR is perpendicular to PQ (where C is the center (3, -2)), we have:
m(−53−3−53m+3)=−1
Simplifying:
m2−5m+6=0
m=2 or 3
Both values lie in the range 2≤m<4.
JEE Advanced · 2019 · 27 May 2019 · Paper 1 · Single correct option