A question of numbers (one for the maths fans)

Hey now, some of us engineers actually get that formal math stuff

That's correct, it's a VERY important mathematical concept.The entire discipline of calculus is largely based upon this concept being valid. The computer you are using is dependent on that concept being valid (electron potential wells, circuit analysis, etc).Infinity is a perfectly valid concept.

To really understand infinity you need to learn about limits and series....Seriously, once you understand inifinite series having finite sums and limits it will all make sense to you.Pre-calculus and introductory calculus is a great place to start.

I'm not sure what you mean..... Infinity is a mathematical concept that has been defined by humans. It certainly does exist as a mathematical concept and is perfectly valid. Infinity (when discussing mathematics) is like an imaginary number.... it's something we have given a definition to because it is a useful concept.There is no question of infinity existing in a mathematical sense.

No, you STILL DON'T understand.Infinity is simply an abstract mathematical concept that WE have defined.There is no leap of faith. You are confusing some generic concept of inifinity with the mathematical definition of infinity..9999............ = 1 is true under the system of mathematics that humans have defined for our use. There is no leap of faith or anythiing. It's like an imaginary number. It exists in our system of mathematics under definitions we have created for it.

Have you ever taken Calculus or studied infinite series? If not, I can totally understand how some of this wouldn't make sense.The proof of .9999.............. = 1 using the limit of a converging series is rock solid. Once you can understand that proof everything will make sense to you.Maybe this will help:http://www.math.utah.edu/...on/teaching/calculus/series.htmlThe key to all this is that .9999...... is a CONVERGENT series.http://www.maths.abdn.ac.uk/.../tch/ma2001/notes/node49.htmlHere's one more page on it...Series - Wikipedia(mathematics)

You may be correct in a general sense. Of course the infinity we are discussing here is a mathematical concept created by humans so it certainly exists as an abstract concept It's like a word... Does a word really exist outside of the abstract concept of language?