xy/(x-y)

New concept and I'm having trouble with ones that are not linear equations. Could someone help me out?

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- Feb 9th 2009, 07:01 PMsfgiants13Find all 2nd partial derivatives
xy/(x-y)

New concept and I'm having trouble with ones that are not linear equations. Could someone help me out? - Feb 9th 2009, 07:46 PMJhevon
linear, non-linear, makes little difference. you want to find $\displaystyle \frac {\partial ^2 f}{\partial x ^2}$ and $\displaystyle \frac {\partial ^2 f}{\partial y^2}$ for $\displaystyle f(x,y) = \frac {xy}{x - y}$

to find the first, differentiate with respect to x twice. that is, treat y as a constant. so you would just differentiate normally thinking of y as just any other number, like 2 or something.

a similar approach can get you $\displaystyle \frac {\partial ^2 f}{\partial y^2}$

can you start? - Feb 9th 2009, 07:48 PMChris L T521
- Feb 9th 2009, 07:54 PMJhevon