JEE MAIN - Mathematics (2024 - 6th April Morning Shift - No. 10)
Let $$y=y(x)$$ be the solution of the differential equation $$\left(2 x \log _e x\right) \frac{d y}{d x}+2 y=\frac{3}{x} \log _e x, x>0$$ and $$y\left(e^{-1}\right)=0$$. Then, $$y(e)$$ is equal to
$$-\frac{3}{\mathrm{e}}$$
$$-\frac{3}{2 \mathrm{e}}$$
$$-\frac{2}{3 \mathrm{e}}$$
$$-\frac{2}{\mathrm{e}}$$
Explanation
$$\begin{aligned}
& (2 x \log x) \frac{d y}{d x}+2 y=\frac{3}{x} \log x \\
& \frac{d y}{d x}+\frac{y}{x \log x}=\frac{3}{2 x^2} \\
& I F=e^{\int \frac{1}{x \log x}}=e^{\log (\log x)}=\log x \\
& y \times \log x=\int \log x \times \frac{3}{2 x^2} d x+C \\
& y \log x=\frac{3}{2}\left[\frac{-\log x}{x}-\frac{1}{x}\right]+C \\
& y\left(e^{-1}\right)=0 \\
& \Rightarrow 0=\frac{3}{2}[e-e]+C \\
& C=0 \\
& y \log x=\frac{-3}{2}\left[\frac{\log x+1}{x}\right] \\
& y(e) \rightarrow y(e) \times 1=\frac{-3}{2}\left[\frac{1+1}{e}\right]=-\frac{3}{e}
\end{aligned}$$
Comments (0)
