Limits of multivariable functions

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SUMMARY

The discussion centers on evaluating the limit of the multivariable function \(\frac{y^{2}\sin^{2}x}{x^{4}+y^{4}}\) as \((x,y) \to (0,0)\). The initial approach of substituting \(y=x\) leads to an indeterminate form \(0/0\), prompting the question of whether L'Hospital's rule can be applied. Participants emphasize that L'Hospital's rule is not applicable in multivariable limits, and they highlight the importance of examining limits along different paths, such as straight lines versus parabolas, to determine the overall limit behavior.

PREREQUISITES
  • Understanding of multivariable calculus concepts
  • Familiarity with limits and continuity in multiple dimensions
  • Knowledge of L'Hospital's rule for single-variable functions
  • Ability to analyze limits along various paths
NEXT STEPS
  • Study the application of limits in multivariable calculus
  • Learn about path-dependent limits and their implications
  • Explore alternative methods for evaluating multivariable limits, such as polar coordinates
  • Review examples of limits that yield different results based on the path taken
USEFUL FOR

Students studying multivariable calculus, educators teaching calculus concepts, and anyone interested in understanding the complexities of limits in higher dimensions.

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Homework Statement



The limit as x,y → 0

\frac{y^{2}Sin^{2}x}{x^{4}+y^{4}}

Homework Equations





The Attempt at a Solution



There are pretty straight forward but I have a general question about them. So say in the function above I let y=x and let x approach 0.

I get 0/0 - inconclusive. Can I fall back on single variable calculus and use L'Hospital's rule to find the limit? For some reason my gut tells me no.
 
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If you approach along a straight line, you would need to use L'Hospital's rule to find the limit. What happens if you approach along a parabola? Compare that to approaching along a straight line. What can you conclude?
 

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