Limits of Multivariable equations

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SUMMARY

The discussion focuses on finding the limit of the expression (x^2+y^2)(ln(x^2+2y^2)) as (x,y) approaches (0,0). The limit is identified as an indeterminate form of 0(-infinity). The user attempts to apply L'Hôpital's Rule but encounters further indeterminate forms. A suggestion is made to modify the expression by changing 2x^2 to (2x^2)^-1 instead of altering the logarithmic term.

PREREQUISITES
  • Understanding of multivariable calculus
  • Familiarity with limits and indeterminate forms
  • Knowledge of L'Hôpital's Rule
  • Basic logarithmic properties and transformations
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  • Study the application of L'Hôpital's Rule in multivariable limits
  • Learn about the properties of logarithmic functions in calculus
  • Research techniques for resolving indeterminate forms
  • Explore alternative methods for evaluating limits in multivariable calculus
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Students and professionals in mathematics, particularly those studying calculus and multivariable functions, as well as educators seeking to understand limit evaluation techniques.

cappygal
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I need to find the limit as x,y->0 of (x^2+y^2)(ln(x^2+2y^2)) anylitically.
since the limit of this is 0(-infinity) which is indeterminant .. I tried to approach it along the line y=x which gives:
lim(x->0) of [2x^2*ln(3x^2)]. Again, that gives 0(-infinity). Now, I haven't done calculus in 6 months .. I know I need to get it to a quotient indeterminant form in order to be able to use l'hopital's rule ..
I tried:
lim (x->0) of [2x^2/(ln(3x^2)^-1] but that gives 0/(1/(-infinity) .. that's indeterminant, so I can take the derivative, and get:
lim (x->0) of [4x/(-1(ln(3x^2)^-2)(1/(3x^2))(6x)]
which is
lim (x->0) of [(4x*3x^2)/(-6xln(3x^2)^-2)] which is 0/0 ..
I don't think this is getting me anywhere. Any ideas on how to make this work? Thanks!
 
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Instead of changing [itex]\ln\left(3x^2\right)[/itex] to [itex]\left(\ln\left(3x^2\right)\right)^{-1}[/itex], try changing [itex]2x^2[/itex] to [itex]\left(2x^2\right)^{-1}[/itex].
 

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