NTA Abhyas JEE Main2020MathematicsDifferential EquationsPractice
The differential equation obtained by eliminating the arbitrary constants a and b from x y = a e x + b e - x is
Options
- Ax d 2 y d x 2 + 2 d y d x - x y = 0
- Bd 2 y d x 2 + 2 y d y d x - x y = 0
- Cx d 2 y d x 2 + 2 d y d x + x y = 0
- Dd 2 y d x 2 + d y d x - x y = 0
Correct answer
A. x d 2 y d x 2 + 2 d y d x - x y = 0
Step-by-step solution
Given, x y = a e x + b e - x ..... (I) ⇒    x   d y d x + y = a e x - b e - x ⇒    x   d 2 y d x 2 + d y d x + d y d x = a e x + b e - x ⇒    x   d 2 y d x 2 + 2   d y d x - x y = 0 [from eq. (I)]