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NTA Abhyas JEE Main2020MathematicsCirclePractice

A circle is drawn whose centre is on the x – a x i s and it touches the y - a x i s . If no part of the circle lies outside the parabola y 2 = 8 x , then the maximum possible radius of the circle is

Correct answer

4

Step-by-step solution

Let equation of circle is x - r 2 + y 2 = r 2 Solving it with y 2 = 8 x, we get, x 2 - 2 r x + r 2 + 8 x = r 2 ⇒ x = 0 or x = 2 r - 8 ⇒ r m a x i m u m = 4

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