COMEDK2024Morning ShiftMathematicsCircleActual
The equation of a circle passing through the origin is x^2+y^2-6 x+2 y=0 . The equation of one of its diameter is
Options
- Ax-3 y=0
- Bx+3 y=0
- Cx+y=0
- D3 x-y=0
Correct answer
B. x+3 y=0
Step-by-step solution
The given equation of the circle is x^2 + y^2 - 6x + 2y = 0 . Comparing this with the general equation of a circle x^2 + y^2 + 2gx + 2fy + c = 0 , we have 2g = -6 and 2f = 2 . Thus, g = -3 and f = 1 . The center of the circle is (-g, -f) = (3, -1) . A diameter of a circle is a line passing through its center. Therefore, the equation of the diameter must satisfy the coordinates of the center (3, -1) . Testing the options: For option (1): x - 3y = 3 - 3(-1) = 3 + 3 = 6 0 . For option (2): x + 3y = 3 + 3(-1) = 3 - 3 =