The points of intersection of the line ax+by=0, (a≠ b) and the circle x^2+y^2-2x=0 are A(α ,0) and B(1,β ). The image of the circle with AB as a…
JEE Main 2023 — Mathematics Coordinate Geometry
2023mcqmedium
The points of intersection of the line ax+by=0, (a=b) and the circle x2+y2−2x=0 are A(α,0) and B(1,β). The image of the circle with AB as a diameter in the line x+y+2=0 is :
Official previous-year question
Held on 25 Jan 2023 · Verified 6 Jul 2026.
Options
A
x2+y2+5x+5y+12=0
B
x2+y2+3x+5y+8=0
C
x2+y2+3x+3y+4=0
D
x2+y2−5x−5y+12=0
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Solution
Given,
The points of intersection of the line ax+by=0,(a=b) and the circle x2+y2−2x=0 are A(α,0) and B(1,β) then,
For point A(α,0)
a(α)+b(0)=0⇒α=0
And, α2−2α=0⇒α=0,2
For point B(1,β)
a+bβ=0
Or, β=a−b
And, 1+β2−2=0
⇒β=±1
∵a=b therefore,
Only possibility α=0,β=1
Points are A(0,0) and B(1,1)
So the centre of the circle with diameter AB is (21,21) and radius r=21
Now the image of (21,21) about the line x+y+2=0 is,
1x−21=1y−21=12+12−2(21+21+2)
⇒1x−21=1y−21=−3
⇒Centre of image circle is (−25,−25)
Equation of image circle
(x+25)2+(y+25)2=(21)2
⇒x2+y2+5x+5y+12=0
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