JEE Challenger
More from Straight Lines

Intersection of Line and Circle given Midpoint Coordinate

Suppose a line y=mx+1y = mx + 1 intersects the circle (x−3)2+(y+2)2=25(x - 3)^2 + (y + 2)^2 = 25 at two distinct points PP and QQ. If the xx-coordinate of the midpoint of segment PQPQ equals −35-\frac{3}{5}, then which of the following options is correct?

Options

A

−3≤m<−1-3 \le m < -1

B

2≤m<42 \le m < 4

Correct
C

4≤m<64 \le m < 6

D

6≤m<86 \le m < 8

Step-by-Step Solution

To find the correct range for mm, we substitute the equation of the line y=mx+1y = mx + 1 into the circle (x−3)2+(y+2)2=25(x - 3)^2 + (y + 2)^2 = 25 to form a quadratic equation in xx. Using the relation for the sum of the roots, we set the xx-coordinate of the midpoint x1+x22\frac{x_1 + x_2}{2} equal to −35-\frac{3}{5}, which yields the quadratic equation m2−5m+6=0m^2 - 5m + 6 = 0. Solving this gives m=2m = 2 and m=3m = 3, both of which ensure two distinct points of intersection as the discriminant is strictly positive. Consequently, mm lies in the interval [2,4)[2, 4), making option (B) the correct choice.