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QJEEM24Mad23c: JEE Main 2024 Mathematics - Class 12 JEEM24Mad23c Solution: The solution of the differential equation , is :

The solution of the differential equation (x2+y2)dx−5xy dy=0,y(1)=0(x^2+y^2) \mathrm{d} x-5 x y \mathrm{~d} y=0, y(1)=0 , is :

Multiple Choice Options

  • A ∣x2−4y2∣5=x2\left|x^2-4 y^2\right|^5=x^2
  • B ∣x2−2y2∣6=x\left|x^2-2 y^2\right|^6=x
  • C ∣x2−2y2∣5=x2\left|x^2-2 y^2\right|^5=x^2
  • D ∣x2−4y2∣6=x\left|x^2-4 y^2\right|^6=x

Step-by-Step Verified Solution

amp;(x2+y2)dx−5xydy=0amp;dydx=x2+y25xyamp; Let y=vxamp;dydx=v+xdvdxamp;V+xdvdx=1+v25vamp;xdvdx=1+v2−5v25v\begin{aligned}& \left(x^2+y^2\right) d x-5 x y d y=0 \\& \frac{d y}{d x}=\frac{x^2+y^2}{5 x y} \\& \text { Let } y=v x \\& \frac{d y}{d x}=v+x \frac{d v}{d x} \\& V+x \frac{d v}{d x}=\frac{1+v^2}{5 v} \\& x \frac{d v}{d x}=\frac{1+v^2-5 v^2}{5 v}\end{aligned}

amp;18∫8×5vdv1−4v2=∫dxxamp;−58ln⁡∣1−4v2∣=ln⁡∣x∣+ln⁡camp;⇒58ln⁡∣x2−4y2∣x2+ln⁡∣x∣=ln⁡camp;∣x2−4y2x2∣5/8∣x∣=camp;∣x2−4y2∣5/8∣x∣14=c∵y(1)=0⇒c=1\begin{aligned}& \frac{1}{8} \int \frac{8 \times 5 v d v}{1-4 v^2}=\int \frac{d x}{x} \\& \frac{-5}{8} \ln \left|1-4 v^2\right|=\ln |x|+\ln c \\& \Rightarrow \frac{5}{8} \ln \frac{\left|x^2-4 y^2\right|}{x^2}+\ln |x|=\ln c \\& \left|\frac{x^2-4 y^2}{x^2}\right|^{5 / 8}|x|=c \\& \frac{\left|x^2-4 y^2\right|^{5 / 8}}{|x|^{\frac{1}{4}}}=c \because y(1)=0 \Rightarrow c=1 \\\end{aligned}

amp;⇒∣x2−4y2∣5/8=∣x∣14amp;∣x2−4y2∣5=x2\begin{aligned}& \Rightarrow\left|x^2-4 y^2\right|^{5 / 8}=|x|^{\frac{1}{4}} \\& \left|x^2-4 y^2\right|^5=x^2\end{aligned}

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