How should I show that lim_n ∫〖f_n dm〗 = ∫〖f dm〗?

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In summary, if a sequence of functions {f_n} converges almost everywhere to a function f and the supremum of the absolute values of the functions is bounded, then the limit of the integrals of these functions is equal to the integral of f. This holds true as long as the integrals of the supremums of the functions remain bounded as the sequence approaches infinity.
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Jack3
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Suppose {f_n} is a sequence of functions that converges almost everywhere to a function f
and define F_n = sup_k=1,...n |f_n| .
Show that if the integrals of F_n remain bounded as n goes to infinity,
then lim_n ∫〖f_n dm〗 = ∫〖f dm〗.
 
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Jack said:
Suppose {f_n} is a sequence of functions that converges almost everywhere to a function f
and define F_n = sup_k=1,...n |f_n| .
Show that if the integrals of F_n remain bounded as n goes to infinity,
then lim_n ∫〖f_n dm〗 = ∫〖f dm〗.

Please do not copy and paste text with non-standard characters, not everybodies system will render them correctly, learn to use the LaTeX supported here on MHB and on most other maths boards.

By default avoid non-ASCII characters.

CB
 
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Related to How should I show that lim_n ∫〖f_n dm〗 = ∫〖f dm〗?

1. What is the definition of a limit in calculus?

The definition of a limit in calculus is the value that a function approaches as the input variable gets closer and closer to a certain value or point. It is denoted by the notation "lim".

2. How do I show that the limit of an integral is equal to the integral of the limit?

In order to show that limn→∞n 〖fn dm〗 = ∫〖f dm〗, you must first show that the limit of fn as n approaches infinity exists. Then, you can use the definition of a limit to show that the limit of the integral of fn is equal to the integral of the limit of fn.

3. What are the conditions for the equality of the limit of an integral and the integral of the limit?

The conditions for the equality of the limit of an integral and the integral of the limit are that the limit of the function must exist, the function must be continuous, and the domain of the function must be closed and bounded.

4. Can the limit of an integral be equal to the integral of a different function?

No, the limit of an integral can only be equal to the integral of the same function. This is because the definition of a limit requires the function to approach the same value as the input variable approaches a certain point.

5. Are there any special cases where the limit of an integral is not equal to the integral of the limit?

Yes, there are special cases where the limit of an integral is not equal to the integral of the limit. These cases include when the function is discontinuous, when the domain is not closed and bounded, and when the limit of the function does not exist.

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