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QJEEM25Ma3f58: JEE Main 2025 Mathematics - Class 11 JEEM25Ma3f58 Solution: Let the shortest distance from , to the parabola be 4 . Then…

Let the shortest distance from (a, 0), a>0 , to the parabola y2=4xy^2=4 x be 4 . Then the equation of the circle passing through the point (a,0)(a, 0) and the focus of the parabola, and having its centre on the axis of the parabola is :

Multiple Choice Options

  • A x2+y2−8x+7=0x^2+y^2-8 x+7=0
  • B x2+y2−6x+5=0x^2+y^2-6 x+5=0
  • C x2+y2−4x+3=0x^2+y^2-4 x+3=0
  • D x2+y2−10x+9=0x^2+y^2-10 x+9=0

Step-by-Step Verified Solution

JEE Main 2025 (Online) 23rd January Evening Shift Mathematics - Parabola Question 4 English Explanation

amp; Normal at Pamp;y+tx=2t+t3↑(a,0)\begin{aligned}&\text { Normal at } \mathrm{P}\\&\begin{gathered}y+t x=2 t+t^3 \\\uparrow \\(a, 0)\end{gathered}\end{aligned}

amp;at=2t+t3amp;a=2+t2amp;R(2+t2,0)amp;PR=4⇒4+4t2=16\begin{aligned}& \mathrm{at}=2 \mathrm{t}+\mathrm{t}^3 \\& \mathrm{a}=2+\mathrm{t}^2 \\& \mathrm{R}\left(2+\mathrm{t}^2, 0\right) \\& \mathrm{PR}=4 \Rightarrow 4+4 \mathrm{t}^2=16\end{aligned}

amp;4t2=12⇒t2=3amp;a=5,R(5,0)\begin{aligned}& \quad 4 \mathrm{t}^2=12 \Rightarrow \mathrm{t}^2=3 \\& \mathrm{a}=5, \mathrm{R}(5,0)\end{aligned}

Focus (1,0)(1,0)

(1,0)&(5,0)(1,0) \&(5,0) will be the end points of diameter

⇒Eqn\Rightarrow E q^{\mathrm{n}} of circle is

amp;(x−1)(x−5)+y2=0amp;x2+y2−6x+5=0\begin{aligned}& (x-1)(x-5)+y^2=0 \\& x^2+y^2-6 x+5=0\end{aligned}

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