Sum of (x_n/(1-x_n)) converges if the sum of x_n converges

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SUMMARY

The discussion centers on proving that if the series n=1^∞ xn converges, then the series n=1^∞ (xn/(1-xn)) also converges. The key insight is that as n approaches infinity, xn approaches zero, which allows for bounding the denominator 1-xn. The attempt to apply the Cauchy-Schwarz inequality was noted but deemed ineffective due to potential divergence of 1/(1-xn).

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  • Understanding of series convergence, specifically the convergence of n=1^∞ xn.
  • Familiarity with limits and their properties as n approaches infinity.
  • Knowledge of the Cauchy-Schwarz inequality and its applications in series.
  • Basic understanding of bounding techniques in mathematical analysis.
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  • Investigate the behavior of functions as they approach limits, specifically 1/(1-x) as x approaches zero.
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Homework Statement



I'm trying to show that if

\sum_{n=1}^\infty x_n

converges, then so does

\sum_{n=1}^\infty \frac{x_n}{1-x_n}


Homework Equations



Unknown. Possibly using the limit of the sum of x_n to bound the partial sums of x_n/(1-x_n)?


The Attempt at a Solution



My first thought was to try to combine the Cauchy Schwartz inequality with convergence of the sum of 1/(1-x_n) - but this doesn't help since 1/(1-x_n) can diverge. So I don't know how to proceed with this one.
 
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If the series x_n converges, then limit n->infinity x_n=0. Use that to put a bound on the size of the denominator 1-x_n.
 

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