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TS EAMCET · Maths · Differential Equations

If the solution of the differential equation \(x y^{\prime}=y+x^2 \sin x\) subject to the condition \(y(\pi)=0\) is \(y=f(x)\) and \(f(x)\) has an extreme value at \(x=\alpha\), then

  1. A \(\alpha \cos \alpha+2\)
  2. B \(\alpha=(2 n-1) \frac{\pi}{2}, n \in Z\)
  3. C \(\cos \frac{\alpha}{2}=1\)
  4. D \(\alpha=\cot \frac{\alpha}{2}\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(\alpha=\cot \frac{\alpha}{2}\)

Step-by-step Solution

Detailed explanation

Given differential equation, \(\begin{aligned} x \frac{d y}{d x}-y & =x^2 \sin x \\ \Rightarrow \quad \frac{x d y-y d x}{x^2} & =\sin x d x \Rightarrow \int d\left(\frac{y}{x}\right)=\int \sin x d x \\ \Rightarrow \quad \frac{y}{x} & =-\cos x+c\end{aligned}\)…