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[–] 51 points 9 months ago (11 children)

It’s been a while… but isn’t that negative?

Or is there some default given of which side it’s approaching from.

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  • [–] 26 points 9 months ago* (last edited 9 months ago)

    (Just including the graph for reference. I'm not sure it helps with proper description or the answer the teacher was asking for, but you can see that from one direction it goes negative as you approach 8 and from the other it goes to positive infinity.)

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  • [–] 35 points 9 months ago* (5 children)

    I think it is not defined. It has a limes from the left (- inf) and limes from the right (+ inf) but no two-sided limes.

    Edit: wolframalpha agrees but I don't know for sure

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  • [–] 18 points 9 months ago (3 children)

    It has a limes from the left… and limes from the right…

    Is that the Tootsie Roll Theorem?

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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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  • [–] 31 points 9 months ago* (last edited 9 months ago) (4 children)

    Just here to comment on the weird spreadsheet format (of that oooooold joke)

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  • [–] 26 points 9 months ago (5 children)

    That’s a ChatGPT kind of answer. A pattern is recognized, but the meaning isn’t understood.

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  • [–] 21 points 9 months ago (3 children)

    There's no way ChatGPT would be creative enough to put a number on its side

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  • [–] 12 points 9 months ago

    The first one is incorrect, the limit doesn't exist unless you specify whether you're coming from the left or right.

    On another note, I think their student has invented a new symbol for "Does Not Exist".

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  • [–] 26 points 9 months ago (1 child)

    That is not infinity, its undefined.

    This only works if you use a one sided limit.

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  • [–] 12 points 9 months ago (1 child)
  • [–] 4 points 9 months ago

    Story time, third grader me would have done this no questions about it.

    Having to solve multiplication and recently had learned the table of 9 trick i was looking if there where other tricks I could find.

    The first one was number x10 and what i observed is that if you do times ten. You take the number. And you put 1 “0” behind it.

    Interesting…. I thought

    But the next one multiplied with a single digit so how could i apply that theory.

    Simple. 1+0 is 1, which is a single digit so if you multiply by 10, you actually multiply by 1+0 which means you put 1 zeros behind it

    Multiple by 2 is short for multiply By 2+0, put 2 zeros behind it

    Multiply by 9, put 9 zeros behind it.

    I definitely knew this is not what we had learned, and knew there was a “chance” i was going to fail all of these, i also even knew some of the actual answers however i also believed there was a chance that i found an alternative equally good solution, and I consciously decided to take that risk because I wanted to know if i was right. Maybe I discovered something new

    My teacher was not happy to say the least, and in that (actual) furry did treat me unfair and it still bothers me. Because i got a zero for the assignment.. while i was very certain that the 2 occurrences of x10 did have the appropriate solution.

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  • [–] 2 points 9 months ago

    This is why we need quantum computing. Traditional computing doesn't account for sideways numbers.

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  • [–] 2 points 9 months ago

    Specification gaming lol

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  • [–] 1 point 9 months ago

    This has me dead like that 8 and 5.

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  • [–] 1 point 9 months ago

    lim means glue in Swedish.

    That's all I know.

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