Infinity...

[helpplz]

this has made me very mad for a very long time because my bro doesn't want to think outside the "box", or inside my "box" long enough to at least give me an opinion that does not peg me as a retard with flawed logic.

now you know Pi right? that number no one has ever found the end of, said to be a number that never ends. Well i was thinking, if you said Pi times 2 you would still get a number that never ends. Which brings me to my next point, if you just said infinity times 2 you would not get a number because you can't, but, think about this, if you put a variable into infinity, like .2 repeating which is .2 that of course goes on forever, then is it not possible to multiply .2infinity/repeating BY 2?

I have done that on a calculator and i never got a number that had a decimal that did not go on forever.

so this brings me to the point of my thread, if you put a number variable into infinity can you not multiply it by 2? Give me your opinion to put my mind at rest please....

[Modred]

It's not that complicated. If you have .2 repeating multiplied by 2, then you end up with .4 repeating. Simple logic says that if each .2 will double when multiplied by 2.

The point is that you aren't multiplying infinity and a number, but you are simply multiplying a number with an infinite number of digits by another number. You don't need to know all of the digits to get an accurate answer. On that note, the average computer using 32-bit double precision arithmetic generally has a default of 16 decimal places precision. That's more than enough for the average arithmetic problem, but very manageable from a machine's standpoint.

[Darkslayer633]

It's not that complicated. If you have .2 repeating multiplied by 2, then you end up with .4 repeating. Simple logic says that if each .2 will double when multiplied by 2.

The point is that you aren't multiplying infinity and a number, but you are simply multiplying a number with an infinite number of digits by another number. You don't need to know all of the digits to get an accurate answer. On that note, the average computer using 32-bit double precision arithmetic generally has a default of 16 decimal places precision. That's more than enough for the average arithmetic problem, but very manageable from a machine's standpoint.


in short, your number ends because the calculator cant show any more numbers so it rounds off the number.

[OboeGuru]

As Modred said, you're simply confusing the concepts of a non-terminating decimal (infinitely repeating series) and infinity itself, which is not a number but rather the concept of having limitless value.
The number you mentioned .22222... has a value, 2/9, so it can be multiplied by a constant to achieve a new value, .444444... which is valued at 4/9.
Pi, while both non-terminating and irrational, is an actual value and can thus be multiplied by a constant as well. The same goes for [I]e.

I'm not even going to touch [I]i, because complex numbers are ... interesting.