How Do You Solve Double Limits Involving Two Variables?

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In summary, a double limit is a mathematical concept that represents the behavior of a function as two variables approach a specific point simultaneously. To find a double limit, you need to first determine the limit of the function as each variable approaches the specified point separately and then combine these two limits. The difference between a single and a double limit is that a single limit involves one variable approaching a point while a double limit involves two variables approaching a point. The properties of double limits include the sum, product, quotient, and composition properties, which simplify the process of evaluation. L'Hopital's rule should be used when evaluating a double limit that results in an indeterminate form.
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utkarshakash
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Homework Statement


[itex]\stackrel{lim}{y→0}\left( \stackrel{lim}{x→∞} \dfrac{\left( 1+\dfrac{ay}{x} \right)^x - \left( 1+\dfrac{by}{x} \right)^x}{y} \right)[/itex]

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The Attempt at a Solution


I need some hints. I really don't know how to solve these kinds of limits in which two variables are involved.
 
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  • #2
Just do the inner one first with y held constant, then do the outer one. If you know how to do one-dimensional limits then these are just as easy!
 
  • #3
You need to know that [itex]\lim_{x\to \infty}\left(1+ \frac{a}{x}\right)^x=e^a[/itex]
 

FAQ: How Do You Solve Double Limits Involving Two Variables?

What is a double limit?

A double limit is a mathematical concept that represents the behavior of a function as two variables approach a specific point simultaneously. It is the limit of a function in two directions.

How do I find a double limit?

To find a double limit, you need to first determine the limit of the function as each variable approaches the specified point separately. Then, you can combine these two limits to find the double limit.

What is the difference between a single and a double limit?

A single limit involves the behavior of a function as one variable approaches a specific point, while a double limit involves the behavior of a function as two variables approach a specific point simultaneously.

What are the properties of double limits?

The properties of double limits include the sum property, product property, quotient property, and composition property. These properties allow us to simplify the process of evaluating double limits.

When should I use L'Hopital's rule to find a double limit?

L'Hopital's rule should be used when evaluating a double limit that results in an indeterminate form, such as 0/0 or ∞/∞. This rule allows us to find the limit by taking the derivatives of the numerator and denominator and evaluating the resulting limit.

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