Does the Limit Exist? Check to Find Out!

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SUMMARY

The discussion centers on evaluating the limit $$\lim_{(x, y) \rightarrow (0, 0)} \frac{\sin 2x-2x+y}{x^3+y}$$ using different approaches. It is established that along the trajectory $y=0$, the limit equals $-\frac{4}{3}$, while along the trajectory $y = 2x - \sin 2x$, the limit equals 0. This discrepancy indicates that the limit does not exist as it depends on the path taken to approach the point (0,0).

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  • Understanding of limits in multivariable calculus
  • Familiarity with De L'Hôpital's Rule
  • Knowledge of evaluating limits along different paths
  • Basic understanding of trigonometric functions and their properties
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  • Explore the concept of continuity and limits in higher dimensions
  • Investigate other examples of limits that do not exist due to path dependency
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mathmari
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Hey! :o

I have found applying De L'Hoptal's Rule that $$\lim_{x \rightarrow 0} \frac{\sin 2x-2x}{x^3}=-\frac{4}{3}$$

Now I am asked whether the limit $$\lim_{(x, y) \rightarrow (0, 0)} \frac{\sin 2x-2x+y}{x^3+y}$$ or not.

How could we check that ?? (Wondering)
 
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mathmari said:
Hey! :o

I have found applying De L'Hoptal's Rule that $$\lim_{x \rightarrow 0} \frac{\sin 2x-2x}{x^3}=-\frac{4}{3}$$

Now I am asked whether the limit $$\lim_{(x, y) \rightarrow (0, 0)} \frac{\sin 2x-2x+y}{x^3+y}$$ or not.

How could we check that ?? (Wondering)

Hi! (Wave)

I would start with checking what the limit is on different lines, say $y=0$ respectively $x=0$. (Thinking)
 
mathmari said:
Hey! :o

I have found applying De L'Hoptal's Rule that $$\lim_{x \rightarrow 0} \frac{\sin 2x-2x}{x^3}=-\frac{4}{3}$$

Now I am asked whether the limit $$\lim_{(x, y) \rightarrow (0, 0)} \frac{\sin 2x-2x+y}{x^3+y}$$ or not.

How could we check that ?? (Wondering)

If $(x,y) \rightarrow (0,0)$ along the trajectory y=0 the limit is $- \frac{4}{3}$ as You have found... if $(x,y) \rightarrow (0,0)$ along the trajectory $y = 2\ x - \sin 2x$ the limit is 0... what do You can conclude?...

Kind regards

$\chi$ $\sigma$
 

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