The differential equation satisfied by the system of parabolas
y2 = 4a(x + a) is :
Solution
${y^2} = 4ax + 4{a^2}$<br><br>differentiate with respect to x<br><br>$\Rightarrow 2y{{dy} \over {dx}} = 4a$<br><br>$\Rightarrow a = \left( {{y \over 2}{{dy} \over {dx}}} \right)$<br><br>So, required differential equation is <br><br>$${y^2} = \left( {4 \times {y \over 2}{{dy} \over {dx}}} \right)x + 4{\left( {{y \over 2}{{dy} \over {dx}}} \right)^2}$$<br><br>$$ \Rightarrow {y^2}{\left( {{{dy} \over {dx}}} \right)^2} + 2xy\left( {{{dy} \over {dx}}} \right) - {y^2} = 0$$<br><br>$$ \Rightarrow y{\left( {{{dy} \over {dx}}} \right)^2} + 2x\left( {{{dy} \over {dx}}} \right) - y = 0$$
About this question
Subject: Mathematics · Chapter: Differential Equations · Topic: Order and Degree
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