NTA Abhyas JEE Main2020MathematicsDifferential EquationsPractice
The slope of normal at any point P of a curve (lying in the first quadrant) is reciprocal of twice the product of the abscissa and the ordinate of point P . Then, the equation of the curve is (where, c is an arbitrary constant)
Options
- Ay 2 = x + c
- By = c e − x 2
- Cy = c e - x
- Dy 2 = ln x + c
Correct answer
B. y = c e − x 2
Step-by-step solution
Slope of normal at P = - 1 d y d x P ⇒ 1 2 x y = - 1 d y d x or d y d x = - 2 x y ⇒ ∫ d y y = ∫ - 2 x d x ⇒ ln y = - x 2 + k ⇒ y = e − x 2 + k = c e − x 2