JEE Main20209 Jan 2020Morning ShiftMathematicsCircleActual
A circle touches the y-axis at the point 0 , 4 and passes through the point 2 , 0 . Which of the following lines is not a tangent to this circle?
Options
- A4 x - 3 y + 17 = 0
- B3 x - 4 y - 24 = 0
- C3 x + 4 y - 6 = 0
- D4 x + 3 y - 8 = 0
Correct answer
D. 4 x + 3 y - 8 = 0
Step-by-step solution
Equation of family of circle x - 0 2 + y - 4 2 + λ x = 0 ⇒ p a s s e s 2 , 0 4 + 16 + 2 λ = 0 ⇒ λ = - 10 x 2 + y 2 - 10 x - 8 y + 16 = 0 Centre 5,4 , R = 25 + 16 - 16 = 5 Check the options. Option (4) 4 × 5 + 3 × 4 - 8 5 = 24 5 ≠ 5