2. Определите тип уравнений, если u = f (x, y):
| \(\displaystyle 6\frac{\partial^2 u}{\partial x^2} - 3\frac{\partial^2 u}{\partial y^2} - \frac{\partial u}{\partial x} + 7u = 0\) |
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| \(\displaystyle \frac{\partial^2 u}{\partial x^2} + \frac{\partial u}{\partial y} = 3y\) |
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| \(\displaystyle 2\frac{\partial^2 u}{\partial x^2} = 0{,}5\frac{\partial^2 u}{\partial y^2} - u + 8\frac{x}{y} = 0\) |
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| \(\displaystyle -11\frac{\partial^2 u}{\partial y^2} + 9\frac{\partial u}{\partial x} = 7u - 2y\) |
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| \(\displaystyle 4\frac{\partial^2 u}{\partial x^2} = -6\frac{\partial^2 u}{\partial y^2} + 3\frac{\partial u}{\partial x} - 7y\) |
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