Solving Multi-Limits: x to 0, y to 0

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SUMMARY

The limit of the function \( \lim_{(x,y) \to (0,0)} (xy \ln(x^2 + y^2)) \) is determined to be zero when approached using the path \( y = x \). However, when using the path \( y = \frac{1}{x} \), the limit approaches infinity, indicating that the limit does not exist overall. Converting the expression to polar coordinates and letting \( r \to 0 \) confirms that the limit is indeed zero. The discussion emphasizes the importance of path dependency in evaluating limits in multivariable calculus.

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Homework Statement


solve
[tex]{\lim }\limits_{\scriptstyle x \to 0 \hfill \atop <br /> \scriptstyle y \to 0 \hfill} (xy\ln \left( {x^2 + y^2 } \right))[/tex]

Homework Equations


[tex]y_{1}=x[/tex]
[tex]y_2=1/x[/tex]

The Attempt at a Solution


when using [tex]y_{1}=x[/tex] we get that the limit is zero
when using this [tex]y_{2}=1/x[/tex] we get that the limit is infinity
thus the limit does not ! exist.
i don't know if it is ok to use these 2 paths i some how have a feeling that the second one is wrong
thanks for the help
 
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Convert it to polar and let r->0. You get that the limit is zero. Also, the whole idea of using a path is to show the limits do not exist by showing that if you approach the point 0,0 along different paths then you get different limits. y = 1/x never approaches (0,0)
 

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