AP EAMCET20224 Jul 2022Morning ShiftMathematicsDifferential EquationsActual
y = A e x + B e - 2 x satisfies which of the following differential equations?
Options
- Ad 2 y d x 2 - d y d x + 2 y = 0
- Bd 2 y d x 2 - 2 d y d x - y = 0
- Cd 2 y d x - 2 d y d x + y = 0
- Dd 2 y d x 2 + d y d x - 2 y = 0
Correct answer
D. d 2 y d x 2 + d y d x - 2 y = 0
Step-by-step solution
y = A e x + B e - 2 x On differentiating, we get d y d x = A e x - 2 B e - 2 x Subtracting both the above equations, we get y - d y d x = 3 B e - 2 x or y e 2 x - d y d x e 2 x = 3 B Differentiating above equation, we get 2 y e 2 x + e 2 x d y d x - 2 e 2 x d y d x - e 2 x d 2 y d x 2 = 0 ⇒ 2 y - d y d x - d 2 y d x 2 = 0