Posted by **Eleonora** on Tuesday, September 8, 2009 at 10:52pm.

Is .121221222122221... (the pattern in this number continues forever) a rational number or irrational number? Why?

(my research is listed in a previous question post, but I'm stuck!!! Please help!) :-)

- Math -
**MathMate**, Tuesday, September 8, 2009 at 11:07pm
Each term 0.12, 0.00122, 0.000001222, 0.00000000012222, ...

is a rational number. When continued forever and added together, it does not have to be a rational number.

Another example:

1, 1/3, 1/5, 1/7, 1/9, ... are all rational numbers.

If we look at the sum

S = 1 - 1/3 + 1/5 - 1/7 + 1/9 - ....

S equals π/4, a known irrational number.

In fact, a non-recurring decimal number is considered an irrational number.

See:

http://en.wikipedia.org/wiki/Irrational_number

- Math -
**camy**, Wednesday, September 9, 2009 at 1:00am
you have to put in the division,addition,sub., or whatever to answer this...(44,8,74,21,4)=10

- Math -
**MathMate**, Wednesday, September 9, 2009 at 7:41am
Camy,

It is not a good idea to piggyback a question on someone else's question. It may get ignored or overlooked.

As there are no replies yet, I suggest you repost the question as a new thread.

Thank you.

## Answer This Question

## Related Questions

- Math - What are irrational, rational, and natural numbers? A rational number is ...
- 8th Grade Math - Please help! Which statement is false? A. The number zero is a ...
- math- please help - What is the best sequence of names to identify this set of ...
- MATH HELP PLEASE - Which statment is false? A. The number zero is a rational ...
- Math - Which statement is false? A. The number zero is a rational number. B. ...
- Math Check Pleas Thank You - 1. Which of the following numbers is an example of ...
- math - What is the best sequence of names to identify this set of numbers? (1 3/...
- math - 1. Which of the following numbers is an example of an integer? a. -15 b. ...
- Math - In the question: a rational number plus an irrational number will be ____...
- math - which number has the greatest value? a 3.5 b square root of 15** c square...

More Related Questions