Solving Multivariable Limit: Find Limit or Show No Existence

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SUMMARY

The discussion focuses on evaluating the limit of the function (x^2 * sin^2y)/(x^2 + 2y^2) as (x,y) approaches (0,0). The initial attempts to find the limit using the lines x=0 and y=0 both yielded a limit of 0. However, further verification is necessary by checking additional paths, specifically by substituting x = y and y = x, to confirm the limit's existence. The conclusion emphasizes the importance of testing multiple approaches to ensure the limit is consistent across different paths.

PREREQUISITES
  • Understanding of multivariable calculus limits
  • Familiarity with trigonometric functions, specifically sin^2
  • Knowledge of limit definitions and epsilon-delta proofs
  • Ability to analyze functions using different paths in the xy-plane
NEXT STEPS
  • Study the epsilon-delta definition of limits in multivariable calculus
  • Learn about path independence in multivariable limits
  • Explore the use of polar coordinates for evaluating limits
  • Investigate the Squeeze Theorem as it applies to multivariable functions
USEFUL FOR

Students and educators in calculus, particularly those focusing on multivariable limits, as well as mathematicians seeking to deepen their understanding of limit evaluation techniques.

Laura1321412
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Homework Statement



Find that the limit exists, or show that the limit does not exist.

lim (x,y) --> (0,0) of (x^2 * sin^2y)/(x^2 + 2y^2)


Homework Equations


??

The Attempt at a Solution



i used the lines x=0 y=0 and both times got the limit 0 so i attempted to prove the limit exists

I attempted to use the limit definition,

1 >= |sin^2| >= 0
x^2 + 2y^2 >= x^2
x^2+2y^2 >= x^2sin^2y
|x^2sin^2y/x^2+2y^2| <= 1

uhmm... I am not sure what do after this or really what the heck I am doing. HELP? :)
 
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You are forgetting to check one last condition before proving that the limit exist! Not sure if it would do anything but try plugging x = y and y = x. If this checks out ( = 0) then you can be sure that the limit exist and try to prove it.
 

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