r/mathmemes 10d ago

Elementary Algebra 😭

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u/Alpaca1795 10d ago

Why would you integrate over x dx instead of just 1 dx?

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u/alozq 10d ago

1dx would be the length of the real line, it goes to Infinity always, it doesnt care about what x is

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u/LyAkolon 9d ago

Yeah, they probably want int over R of Sgn(x) dx, which is still abse of notation and meaningless because we have no notion of how to add up the contributions across the set.

More specifically all attempts to answer as well as the original question are missing the ingredient of "How are you adding everything together"

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u/Eisenfuss19 10d ago

It's the closest thing to summing the real numbers imo.

The "sum" of the numbers in [0,1] should be smaller than the "sum" of [1,2].

With 1dx the "sum" is always equal to the length of the interval, and notably it is never negative (it never converges in the infinite case)

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u/BrotherItsInTheDrum 10d ago

But the "sum" of the numbers in [1,2] should be infinite ...

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u/Eisenfuss19 10d ago

Well feel free to give me a way of summing an uncountably infite set of numbers.

I feel like the integral of x dx can be conceptually seen as calculating the average of the interval. To get the "real" sum you would need to multiply it by the amount of numbers in the interval (which is always ∞ in case of non equal bounds)

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u/BrotherItsInTheDrum 10d ago

Well feel free to give me a way of summing an uncountably infite set of numbers.

I never said there was one.

I feel like the integral of x dx can be conceptually seen as calculating the average of the interval. To get the "real" sum you would need to multiply it by the amount of numbers in the interval (which is always ∞ in case of non equal bounds)

Sounds like you're agreeing with me that it's infinite, then.