NTA Abhyas JEE Main2020MathematicsDifferential EquationsPractice
The equation of the curve lying in the first quadrant, such that the portion of the x -axis cut-off between the origin and the tangent at any point P is equal to the ordinate of P , is (where, c is an arbitrary constant)
Options
- Ay = c e x y
- By e x y = c
- Cy e y x = c
- Dy = c e y x
Correct answer
B. y e x y = c
Step-by-step solution
Equation of the tangent at P x , y is Y - y = d y d x X - x Putting Y = 0 , we get, X = x - y y ' = y ∴ d x d y - x y = - 1 is a linear differential equation. Ι . F . = e - ln y = 1 y Thus, the solution is x 1 y = ∫ - 1 1 y d y or x y = - ln y + ln c ⇒ c y = e x y Hence, y e x y = c is the equation of the curve