Jump to content
GreaseSpot Cafe

Rearragngemerents


Ham
 Share

Recommended Posts

Like the series 1 - 1/2 + 1/3 - 1/4 + 1/5 - 1/6 + ... = ln2.

ln2 is a real number. Approximately equal to .6931

if you re-arrange the series, say like:

1 + 1/3 - 1/2 + 1/5 + 1/7 - 1/4 ...

you still use up all of the same terms. However, the sum will be greater.

The real weird thing about this. One can simply pick a number. Any number.. and one can find a re-arrangement of the series which will sum to that number.

It might be a *tad* difficult to list the series correctly, but it does exist.

Link to comment
Share on other sites

If you want the number to be infinity in the extended real number system.. simply choose to sum all of the positive terms first.. 1 + 1/3 + 1/5 + 1/7 + 1/9 + ...

This series diverges. In other words, is not bound by any real number.

It "blows up" even before one gets a chance to add on any negative terms..

Link to comment
Share on other sites

I always liked series and sequences.

So far, except for infinity, the extended real numbers and such, I haven't used anything here past high school algebra. We're just adding fractions.

of course to show the sum of 1 - 1/2 + 1/3 - 1/4 + 1/5 - 1/6 + ... is really ln2, requires a tad more. but one could take a calculator, start adding and subtracting fractions and observe the sum gets closer and closer to 0.6931 as one keeps it up..

Did you know, there are two decimal representations of the number 1?

maybe or maybe not. They might look different, but they are in fact the same thing..

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...