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- Thread starter aruwin
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- Feb 5, 2012

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Hi aruwin,I have calculated 3 times and I still don't get the answer. The answer should be 0.

Here's the question and my work. Which part am I wrong?

f(x,y) = 1/√(1-2xy+y^2)

Prove that ∂/∂x{(1-x^2)*∂f/∂x} + ∂/∂y{(y^2)*∂f/∂y} = 0

You have used the quotient rule incorrectly when calculating, \(\displaystyle\frac{\partial}{\partial x}\left[\frac{y(1-x^2)}{(1-2xy+y^2)^{\frac{3}{2}}}\right]\mbox{ and }\frac{\partial}{\partial y}\left[\frac{(x-y)y^2}{(1-2xy+y^2)^{\frac{3}{2}}}\right]\).

Kind Regards,

Sudharaka

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- #3

Oh my gosh, yes. I have found what is wrongHi aruwin,

You have used the quotient rule incorrectly when calculating, \(\displaystyle\frac{\partial}{\partial x}\left[\frac{y(1-x^2)}{(1-2xy+y^2)^{\frac{3}{2}}}\right]\mbox{ and }\frac{\partial}{\partial y}\left[\frac{(x-y)y^2}{(1-2xy+y^2)^{\frac{3}{2}}}\right]\).

Kind Regards,

Sudharaka

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- Feb 29, 2012

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