For the differential equation $x\frac{dy}{dx}+2y= x^2\log_ex$ (A) Integrating factor is $2x$ Choose the correct answer from the options given below. |
(A) and (C) only (B) and (D) only (B) and (C) only (A) and (D) only |
(B) and (C) only |
The correct answer is Option (3) → (B) and (C) only General linear differential equation: $\frac{dy}{dx} + P(x)y = Q(x)$ Integrating Factor (IF): $IF = e^{\int P(x)\,dx}$ General solution: $y \cdot IF = \int Q(x) \cdot IF \, dx + C$ Given equation: $\frac{dy}{dx} + \frac{2}{x}y = x\log_e|x|$ $IF = e^{\int \frac{2}{x}dx} = x^2$ $\Rightarrow \frac{d}{dx}(x^2y) = x^2 \cdot x\log_e|x| = x^3\log_e|x|$ $\int x^3\log_e|x|\,dx = \frac{x^4}{4}\log_e|x| - \frac{x^4}{16} + C$ $x^2y = \frac{x^4}{4}\log_e|x| - \frac{x^4}{16} + C$ $\Rightarrow y = \frac{x^2}{16}(4\log_e|x| - 1) + Cx^{-2}$ Correct options: (B) and (C) |