JEE Main20248 Apr 2024Evening ShiftMathematicsStraight LinesActual
If the image of the point (-4,5) in the line x+2 y=2 lies on the circle (x+4)^2+(y-3)^2=r^2 , then r is equal to:
Options
- A2
- B3
- C1
- D4
Correct answer
A. 2
Step-by-step solution
Image of point (-4,5) x-x₁ a = y-y₁ b =-2 ( a x₁+b y₁+c a^2+b^2 ) Line: x+2 y-2=0 x+4 1 = y-5 2 =-2 ( -4+10-2 1^2+2^2 )= -8 5 x=-4- 8 5 =- 28 5 y=- 16 5 +5= 9 5 Point lies on circle (x+4)^2+(y-3)^2=r^2 aligned & 64 25 + ( 9 5 -3 )^2=r^2 & 100 25 =r^2, r=2 aligned