JEE Main20208 Jan 2020Evening ShiftMathematicsApplication of DerivativesActual
The length of the perpendicular from the origin, on normal to the curve, x 2 + 2 x y - 3 y 2 = 0 , at the point 2 ,   2 , is.
Options
- A2
- B4 2
- C2
- D2 2
Correct answer
D. 2 2
Step-by-step solution
x 2 + 2 x y - 3 y 2 = 0 Differentiate the above curve, 2 x + 2 x y ' + y - 6 y y ' = 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 - 4 1 2 + 1 2 = 4 2 = 2 2 .