1 divided by infinity equals zero (always?)

In summary, the notion that 1 divided by infinity equals zero stems from the concept that as a number approaches infinity, the value of 1 divided by that number gets closer to zero. However, dividing by infinity is not mathematically rigorous since infinity is not a number but rather a concept. Thus, while it is commonly accepted that 1 divided by larger and larger numbers approaches zero, the expression 1/infinity is more of a limit than an actual division, and should be interpreted with caution in mathematical contexts.
  • #1
njh
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1/ infinity = 0, but this seems a simplification.
I understand the mathematics that 1 divided by infinity is virtually zero and so equals zero. I look on the internet and that is the answer that I get. Is this a simplification for early mathematics learning and, if I continue, will I find a more complex answer? The reason that I ask is that I find this a simplification that does not sound right. Thank you.
 
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  • #2
You cannot divide anything by infinity since infinity isn't a number. The notation ##1/\infty =0## is a very sloppy way to write ##\displaystyle{\lim_{n \to \infty}\dfrac{1}{n}=0} ## or whatever else goes to infinity. There is no division by infinity, only the remark that ##\left|\dfrac{1}{n}-0\right|<\varepsilon ## gets arbitrarily small, but not zero.
 
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  • #3
Thank you (and incidentally, my apologies for not using mathematical notation in my question).
 
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FAQ: 1 divided by infinity equals zero (always?)

What does it mean to divide by infinity?

Dividing by infinity is a conceptual way of expressing the idea that as a number gets larger and larger without bound, the result of dividing a finite number by that number approaches zero. In mathematical terms, we often say that the limit of 1 divided by x as x approaches infinity is 0.

Is 1 divided by infinity actually equal to zero?

In strict mathematical terms, dividing by infinity is not defined because infinity is not a number; it is a concept. However, in the context of limits, we can say that the limit of 1/x as x approaches infinity is 0, which means that the value gets arbitrarily close to zero but does not equal zero in a conventional sense.

What is the difference between a limit and an actual division?

A limit is a mathematical concept that describes the behavior of a function as it approaches a certain point, while actual division involves calculating a specific value. When we say 1 divided by infinity approaches zero, we are discussing the limit of the function rather than performing an actual division operation.

Are there any exceptions to the idea that 1 divided by infinity equals zero?

In the standard context of real numbers and limits, there are no exceptions. However, in certain mathematical frameworks, such as projective geometry or extended real numbers, infinity can be treated differently, but these are specialized cases and not part of conventional arithmetic.

How is this concept applied in calculus?

This concept is fundamental in calculus, particularly in understanding limits, continuity, and asymptotic behavior. It helps in evaluating integrals and derivatives where functions approach infinity, allowing mathematicians to analyze behavior at extreme values and make sense of otherwise undefined expressions.

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