Q96 / 150 · MHT CET 2026 (18 April Shift 2) · Mathematics
The integrating factor of the differential equation $x\dfrac{dy}{dx} + 2y = x^2 \log x$ is
- A$x^3$
- Correct answerB$x^2$
- C$\log 2x$
- D$\log x^2$
Solution
The given differential equation is $x\dfrac{dy}{dx} + 2y = x^2 \log x$.
Dividing the entire equation by $x$, we get:
$\dfrac{dy}{dx} + \dfrac{2}{x}y = x \log x$
This is a linear differential equation of the form $\dfrac{dy}{dx} + Py = Q$, where $P = \dfrac{2}{x}$ and $Q = x \log x$.
The integrating factor (IF) is given by $e^{\int P dx}$.
$\text{IF} = e^{\int \dfrac{2}{x} dx}$
$\text{IF} = e^{2 \log x}$
$\text{IF} = e^{\log x^2}$
$\text{IF} = x^2$
Answer: $x^2$
Dividing the entire equation by $x$, we get:
$\dfrac{dy}{dx} + \dfrac{2}{x}y = x \log x$
This is a linear differential equation of the form $\dfrac{dy}{dx} + Py = Q$, where $P = \dfrac{2}{x}$ and $Q = x \log x$.
The integrating factor (IF) is given by $e^{\int P dx}$.
$\text{IF} = e^{\int \dfrac{2}{x} dx}$
$\text{IF} = e^{2 \log x}$
$\text{IF} = e^{\log x^2}$
$\text{IF} = x^2$
Answer: $x^2$
Hence, the correct answer is option: 'B'.