Q26 / 75 · JEE Main 2020 (08 Jan Shift 2) · Mathematics

The length of the perpendicular from the origin, on normal to the curve, x2+2xy-3y2=0, at the point 2, 2, is.

  • A
    2
  • B
    42
  • C
    2
  • Correct answer
    D
    22

Solution

x2+2xy-3y2=0

Differentiate the above curve,

2x+2xy'+y-6yy'=0

So, at 2, 2, y'=1.

So, equation of normal to the curve at 2, 2 is x+y=4.

Thus, perpendicular distance from origin on the normal is

0+0-412+12

=42=22.

Hence, the correct answer is option: 'D'.

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