JEE MainMathematicsCircleMCQ+4 / −1
The length of the diameter of the circle which touches the -axis at the point and passes through the point is :
- A
- B
- C
- D
View written solutionFree
Correct answer: A
-
Use the condition of touching the -axis at
If a circle touches the -axis at , then the radius at the point of contact is perpendicular to the -axis.
Hence the center must lie vertically above or below .
So let the center be where is the radius. Since the circle touches the -axis, its radius is exactly the distance from the center to the -axis, which is . Taking the center above the axis,
-
Use the fact that the circle passes through
The distance from the center to the point must be equal to the radius :
Squaring both sides:
-
Simplify
-
Find the diameter
Diameter :
-
Check options
- A: ✅
- B:
- C:
- D:
Therefore, the correct answer is A.
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