Hi,(adsbygoogle = window.adsbygoogle || []).push({});

there is a proof of the ratio test that I have seen a couple of times here:

http://tutorial.math.lamar.edu/Classes/CalcII/RatioTest.aspx

I dont know how to use latex, so abs(x) will mean absolute value

I am ok with this:

abs( a_{N+1}) < r abs(a_{N})

I dont understand where the r^{2}come from in the next line

abs( a_{N+2}) < r abs(a_{N+1})< r^{2}abs(a_{N})

Similarly, I dont understand how to get to the generalization of

abs( a_{N+k}) < r^{k}abs(a_{N+1})

I should probably add that I understand all other aspects (i.e. using comparison test), but since I don't understand this part, my understanding of the proof fails.

Thanks,

Ivan77

**Physics Forums - The Fusion of Science and Community**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Question about one part of the Ratio Test proof

Loading...

Similar Threads for Question part Ratio | Date |
---|---|

B Function rules question | Mar 17, 2018 |

Question about substitution method in integration | Nov 26, 2014 |

Integration by parts question. | Oct 31, 2013 |

Question on integration by parts | Jun 18, 2013 |

Question about fundamental thm calc part 1 | Dec 3, 2011 |

**Physics Forums - The Fusion of Science and Community**