Comment on (I wonder if he knows about lemmy)1 divided by 0 (a 3rd grade teacher and principal got it wrong), Reddit r/NoStupidQuestions [4:51 | Dec 02 2023 | bprp precalculus]

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magic_lobster_party@kbin.social ⁨11⁩ ⁨months⁩ ago

Quora has many dubious answers. I wouldn’t use it for any point of argument.

Infinity is not a number. It’s a concept. You’ll find yourself in many paradoxes if you start treating infinity as a number (you can easily prove that 1 = 2 for example).

By your argument, is 1/|x| negative infinity when x is 0? The expression is strictly positive, so it doesn’t make sense to assign it a negative value. But your version of infinity would make it both positive and negative.

Another one: try to plot y = (x^2 - 1) * 1/(x - 1). What happens to y when x approaches 1? If you look at a plot, you’ll see that y actually approaches 2. What would happen if we treat 1/(1-1) as your version of infinity? Should we consider that y could also approach -2, even if it doesn’t make any sense in this context?

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