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 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 -3/5, then which one of the following options is correct ?
Given: y=mx+1 cuts (x−3)2+(y+2)2=25 at P,Q
Midpoint of PQ has x=−53
To find: which range of m is correct
Circle:(x−3)2+(y+2)2=25⇒C(3,−2),r=5
y=mx+1 always passes through A(0,1)
M=foot of perpendicular from C onto the line
Line: mx−y+1=0(a=m,b=−1,c=1)
xM=xC−a⋅a2+b2axC+byC+c
xM=3−m2+1m(3m+3)
3−m2+1m(3m+3)=−53
⇒m2+1m(3m+3)=518
5(3m2+3m)=18(m2+1)
3m2−15m+18=0
m2−5m+6=0
(m−2)(m−3)=0⇒m=2 or m=3
d=m2+1∣3m+3∣
m=2:59<5,m=3:1012<5
∠ CMA = 90^∘ ⇒ M lies on the circle with diameter CA