JEE MAIN - Mathematics (2024 - 4th April Morning Shift - No. 13)
If the solution $$y=y(x)$$ of the differential equation $$(x^4+2 x^3+3 x^2+2 x+2) \mathrm{d} y-(2 x^2+2 x+3) \mathrm{d} x=0$$ satisfies $$y(-1)=-\frac{\pi}{4}$$, then $$y(0)$$ is equal to :
$$-\frac{\pi}{12}$$
$$\frac{\pi}{2}$$
0
$$\frac{\pi}{4}$$
Explanation
$$\begin{aligned}
& \left(x^4+2 x^3+3 x^2+2 x+2\right) d y-\left(2 x^2+2 x+3\right) d x=0 \\
& \int d y=\int\left(\frac{2 x^2+2 x+3}{x^4+2 x^3+3 x^2+2 x+2} d x\right. \\
& \int d y=\int \frac{1}{x^2+1} d x+\int \frac{}{x^2+2 x+2} d x \\
& y=\tan ^{-1}(x)+\tan ^{-1}(1+x)+C \\
& y(-1)=\tan ^{-1}(-1)+\tan ^{-1}(1-1)+C \\
& y(-1)=-\frac{\pi}{4}+C=\left(\frac{-\pi}{4}\right)-\{\text { given }\} \\
& \Rightarrow C=0 \\
& \text { So, } y(x)=\tan ^{-1}(x)+\tan ^{-1}(1+x) \\
& y(0)=\tan ^{-1}(0)+\tan ^{-1}(1+0) \\
& y(0)=\frac{\pi}{4}
\end{aligned}$$
Comments (0)
