# NaN variables

**URL:** <https://forum.kirupa.com/t/nan-variables/329433>\
**Category:** flash\
**Created:** [August 28, 2012, 2:49pm UTC](https://forum.kirupa.com/t/nan-variables/329433 "2012-08-28T14:49:35Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![12abhi12](https://avatars.discourse-cdn.com/v4/letter/1/9f8e36/32.png) [@12abhi12](https://forum.kirupa.com/u/12abhi12)\
**Post date:** [August 28, 2012, 2:49pm UTC](https://forum.kirupa.com/t/nan-variables/329433/1 "2012-08-28T14:49:35Z")

</div>

I was making a game and I want to know when a certain variable has gone to not defined. It is condition for an if/else statement. Any way to do it?

I tried equating to another undefined var which I thought would return true but it didn’t work. I also found out that for flash Math.sqrt(-1) != Math.sqrt(-1). Any particular reason?

Thanks in advance.