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Comparison test

Comparison test can mean:Limit comparison test, a method of testing for the convergence of an infinite series.Direct comparison test, a way of deducing the convergence or divergence of an infinite series or an improper…

Comparison test

Comparison test can mean:

  • Limit comparison test, a method of testing for the convergence of an infinite series.
  • Direct comparison test, a way of deducing the convergence or divergence of an infinite series or an improper integral.

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Questions people ask

What is the ε, δ definition actually saying?

That you can make the output as close to the limit as anyone demands (within ε) by keeping the input close enough (within δ). It replaces "approaches" with a challenge-and-response that can be checked.

Why does the harmonic series diverge when its terms go to zero?

Because the terms shrink too slowly: group them as 1/3 + 1/4 > 1/2, 1/5 + … + 1/8 > 1/2, and so on: infinitely many halves.

Parts of this page are adapted from Wikipedia (CC BY-SA 4.0). Condensed and re-explained here; errors are ours.

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