JEE Main202524 Jan 2025Morning ShiftMathematicsCircleActual
Let circle C be the image of x^2+y^2-2 x+4 y-4=0 in the line 2 x-3 y+5=0 and A be the point on C such that O A is parallel to x -axis and A lies on the right hand side of the centre O of C . If B( , ) , with 4 , lies on C such that the length of the are A B is (1 / 6)^ th of the perimeter of C , then - 3 is equal to
Options
- A3+ 3
- B4
- C4- 3
- D3
Correct answer
B. 4
Step-by-step solution
Centre (1,-2), r=3 Reflection of (1,-2) about 2 x-3 y+5=0 aligned & x-1 2 = y+2 -3 = -2(2+6+5) 13 =-2 & x=-3, y=4 aligned Equation of circle ' C ' C:(x+3)^2+(y-4)^2=9 A.T.Q. aligned & ( arcAB )= 1 6 2 r & r = 1 6 2 r & = 3 & ( +6)^2+( -4)^2=27 & ( +3)^2 ( -4)^2=9 ( +6)^2-( +3)^2=18 & 6 =-9 aligned aligned & = -3 2 , = (4- 3 3 2 ) & - 3 & (4- 3 3 2 )+ 3 3 2 & =4 aligned