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Résoudre sur \({\R^2} \setminus \{(0,0)\}\) : \(x\frac{\partial f}{\partial x} = -y\frac{\partial f}{\partial y}\), en posant \(\begin{cases}x = \rho\cos\theta \cr y = \rho\sin\theta. \end{cases}\)
Résoudre sur \({\R^2} \setminus \{(0,0)\}\) : \(x\frac{\partial f}{\partial x} = -y\frac{\partial f}{\partial y}\), en posant \(\begin{cases}x = \rho\cos\theta \cr y = \rho\sin\theta. \end{cases}\)