Prove that all convergent sequences are bounded

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SUMMARY

All convergent sequences are bounded, as established by the proof discussed in the forum. The maximum term of the sequence, denoted as K, is defined as the maximum of all terms plus an additional term of 1 plus the absolute value of the limit L. This ensures that the bound accounts for any initial terms that may exceed the limit, specifically when the inequality |x_n| < L + 1 holds only for n > N. Thus, the largest term among the first N terms is crucial for establishing a valid bound.

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  • Understanding of convergent sequences in real analysis
  • Familiarity with the concept of limits and bounding in mathematical proofs
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converting1
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was looking at a proof of this here: http://gyazo.com/8e35dc1a651cec5948db1ab14df491f8

I have two questions,

why do you set K = max of all the terms of the sequence plus the 1 + |A| term? Why do you need the absolute value of all the terms? i.e. why |a_1| instead of |a_1|?
 
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converting1 said:
was looking at a proof of this here: http://gyazo.com/8e35dc1a651cec5948db1ab14df491f8

I have two questions,

why do you set K = max of all the terms of the sequence plus the 1 + |A| term? Why do you need the absolute value of all the terms? i.e. why |a_1| instead of |a_1|?

Because ##|x_n|< L+1## only holds for ##n > N##. If some of the first ##N## terms are larger than all the rest, use the biggest one of them for the bound.
 

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