How Can the Ratio Test Be Proven for Series Divergence When the Ratio Exceeds 1?

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SUMMARY

The discussion focuses on proving the Ratio Test for series divergence when the ratio exceeds 1. Participants suggest comparing the series to a geometric series and provide examples to illustrate the concept. Specifically, they mention that if the ratio is greater than 1, one can demonstrate that the series diverges by showing that adding a nonzero number infinitely often will surpass any finite value. This establishes a clear method for understanding series divergence using the Ratio Test.

PREREQUISITES
  • Understanding of the Ratio Test in calculus
  • Familiarity with geometric series
  • Basic knowledge of series convergence and divergence
  • Ability to manipulate mathematical inequalities
NEXT STEPS
  • Study the formal definition and proof of the Ratio Test
  • Explore examples of geometric series and their properties
  • Learn about other convergence tests, such as the Root Test
  • Investigate the implications of series divergence in real-world applications
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Students of calculus, mathematics educators, and anyone studying series convergence and divergence, particularly those looking to deepen their understanding of the Ratio Test.

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Homework Statement
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Relevant Equations
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For (a) and (b),
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Does someone please know how to prove this? I don't have any ideas where to start.

Thanks!
 
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a) b) is standard theory.

Relevant examples also included in the link above.
 
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A good starting point is to compare it to a geometric series. For example if ##c=1/3## can you think of a series that converges whose terms are eventually guaranteed to be larger than the ##x_n##?
 
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If the ratio is > 1, then compare to adding a nonzero number to itself " infinitely often", show it will eventually surpass any finite value.
 
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