(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

So the example says fx(0,0)=0 and fy(0,0)=0 (the partial derivatives).

When I try it I'm getting functions that are not defined at (0,0):

f(x,y)=xy/(x[itex]^{}[/itex]+y[itex]^{}[/itex])

so for example,

fx=[x(x^2+y^2)-2y(xy)]/(x^2+y^2)^2

fx=(x^3+xy^2-2xy^2)/(x^2+y^2)^2

fx=x^3-xy^2/(x^2+y^2)^2

Which I keep getting fx(0,0) being undefined. What am I doing wrong?

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# Partial derivative of a function at (0,0)

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