502
Not that limit (lemmy.world)
submitted 9 months ago by to c/science_memes@mander.xyz
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[–] 12 points 9 months ago (3 children)

I have a BA in Mathematics. The limit is indeed determined by the direction you approach the limiting value.

When given without specification, the limit is implied to come from the left, meaning it increases towards the limiting value, which is why you see +inf.

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  • [–] 6 points 9 months ago* (2 children)

    This is just not true. The normal limit we have here means a limit would have to exist from both directions and they should be equal. They're not, so the limit doesn't exist.

    One-sided limits would be denoted by x -> 5– and x -> 5+ or similar.

    PS: in complex analysis, there is no distinction between +infty and -infty, so there it would be correct to say the function has limit infty at 5.

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  • [–] 3 points 9 months ago

    In my experience with maths, there's a whole bunch of different conventions all over the place, so it might've genuinely been how they were taught, even if you were taught differently...

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