Decimals of Pi

True or false: because pi is irrational, any finite sequence of digits MUST be found somewhere in its infinite decimal expansion.

False True

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

2 solutions

Joshua Lowrance
Nov 27, 2018

While it seems unlikely, a finite sequence of digits does not HAVE to be in the decimal expansion of an irrational number. Here is a counter-example: 1.101001000100001000001000000100000001 1.101001000100001000001000000100000001 \cdots . This number is irrational, yet you will never find a 2 2 , 3 3 , 4 4 , 5 5 , 6 6 , 7 7 , 8 8 , or 9 9 in its decimal expansion.

This thought you were specifically speaking about only π π as it does have many sequences within it. You can even find your name there. π π is amazing!!

A Former Brilliant Member - 2 years, 6 months ago

Log in to reply

Yes, pi does have many sequences, but you cannot prove that it has every possible finite sequence.

Joshua Lowrance - 2 years, 6 months ago

Log in to reply

Yeah, but cant even disprove it! See there is indeed a good chance because. You must watch this video from Numberphile in case you haven't. They printed π π upto a million digits!! And they indeed found some sequences.

A Former Brilliant Member - 2 years, 6 months ago

Log in to reply

@A Former Brilliant Member True. I have updated the question. Thank you for bringing this to my attention!

Joshua Lowrance - 2 years, 6 months ago

Log in to reply

@Joshua Lowrance Always welcomed :)

A Former Brilliant Member - 2 years, 6 months ago

I'm pretty sure the actual answer is we don't know. It is still an open question in mathematics as far as I know.

Joe Hill - 2 years, 6 months ago
Jordan Cahn
Nov 28, 2018

It is suspected (but not known) that π \pi is a normal number , which would have the given property. However, this does not follow from its irrationality (as demonstrated by @Joshua Lowrance ).

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...