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QJEEM22Ma23fb: JEE Main 2022 Mathematics - Class 12 JEEM22Ma23fb Solution: Let the locus of the centre ( α , β ) , β > 0 , of the circle…

Let the locus of the centre (α,β),β>0, of the circle which touches the circle x2+(y−1)2=1 externally and also touches the x-axis be L. Then the area bounded by L and the line y=4 is:

Multiple Choice Options

  • A 3223
  • B 4023
  • C 643
  • D 323

Step-by-Step Verified Solution

JEE Main 2022 (Online) 25th July Morning Shift Mathematics - Area Under The Curves Question 67 English Explanation 1
Radius of circle SS touching xx -axis and centre (α,β)(\alpha, \beta) is ∣β∣|\beta| . According to given conditions

α2+(β−1)2=(|β|+1)2α2+β2−2β+1=β2+1+2|β|α2=4β as β>0

∴\therefore \quad Required louse is L:x2=4yL: x^{2}=4 y

JEE Main 2022 (Online) 25th July Morning Shift Mathematics - Area Under The Curves Question 67 English Explanation 2
The area of shaded region =2∫042ydy=2 \int_{0}^{4} 2 \sqrt{y} d y

=4.[y3232]04=643 square units. 

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