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Probably a very simple question for most of you, but how is the relation called between $x$ and $y$ if $y = 1/x$?

As in, if I want to say: $y$ is .... related to $x$, what should go on the dots?

Update: Thank you all for your very quick responses! I was actually looking for the more general $y = c/x$, so the answer I was looking for seems to be "inversely proportional" (and not the more specific "reciprocal", even though that's perhaps a better answer for the $y = 1/x$ relation I mistakenly asked for)

Tiddo
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We say that they are inversely proportional.

Tyr Curtis
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    it's a comment, not an answer ! – idm Feb 01 '15 at 20:15
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    Thanks, this was exactly the answer I was looking for! – Tiddo Feb 01 '15 at 20:16
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    @idm Can you think of any answer to this question which is not a comment? – Tyr Curtis Feb 01 '15 at 20:16
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    @TyrCurtis You should expand on your comment. At least provide something more substantial. Just a moment ago someone asked what the value of $\int_1^e\frac{1}{x},dx$ was...I didn't just write $1$. – Daniel W. Farlow Feb 01 '15 at 20:18
  • @induktio Feel free to edit my answer as you deem fit; I cannot think of a way to make it more substantial. – Tyr Curtis Feb 01 '15 at 20:20
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    This is a complete answer to the question; I don't know why people are being so harsh to it. It's not like there's anything to add here that would be a natural extension of what is given. If someone feels this answer is insufficient they should surely write their own answer, rather than criticize a perfectly valid answer. – Milo Brandt Feb 01 '15 at 20:50
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    If you really want to flesh it out, you could add something like "Generally we say $y$ and $x$ are proportional if $\frac{x}{y}$ is a constant, and inversely proportional if $xy$ is a constant." But I agree, it's a perfectly good answer already. – hasnohat Feb 01 '15 at 20:50
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I think that the most appropriate term to fill in the dots left by Tiddo is reciprocal.

"$y$ is the reciprocal of $x$".

By looking at this article in Wikipedia we learn that this comes from a XVI century translation of Euclid's Elements.

PS. I insist in this terminological vein since Tiddo seems to have said that this was the kind of answer he was expecting. @Tiddo, I suggest that you accept the answer that best suits your purposes.

Pedro Sánchez Terraf
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  • Thank you for your answer! I think I'm looking for inversely proportional though, if I understand the Wikipedia article correctly reciprocal is specific for y = 1/x, but for my intended purpose I'm actually looking for y = c/x. I'll update my question accordingly. – Tiddo Feb 01 '15 at 20:46
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I am pretty sure you are looking for an answer like this: $y$ is inversely related to $x$enter image description here

To find the inverse, just switch $x$ and $y$ and solve for $y$.