How do you call this formula in math terms? Quotient derivative?

Asked May 14 '16 at 19:01

Active May 14 '16 at 19:29

Viewed 49 times

Sorry for that noob question, but I've been searching for ages without finding something...

I've got a series of values $x(n)$. Now to get the derivative I would subtract the current value from the previous: $y(n) = x(n) - x(n-1)$.

But how do you call the process of taking the quotient in the same way? $y(n) = \frac{x(n)}{x(n-1)}$

Thanks!

edited May 14 '16 at 19:29

operatorerror

asked May 14 '16 at 19:01

Gustav Scholda

why do you want a name ? and $x(n)-x(n-1)$ is often called $\Delta x$ the (backward) finite difference of order $1$, hence $\frac{x(n)}{x(n-1)} = e^{\Delta \ln x}$ – reuns May 14 '16 at 19:08
Taking $y(n)=x(n)-x(n-1)$ is not the derivative, rather it's the first backward difference. – Matt Samuel May 14 '16 at 19:09
ok, so how would you call the quotient? First Backward Quotient? The reason I want to know is I whant to search for it so I can find how this is maybe used – Gustav Scholda May 14 '16 at 19:13
I don't know if it has a standard name but if it does it's probably not the first backward quotient. – Matt Samuel May 14 '16 at 19:22
hmm... ok, that doesn't help sadly – Gustav Scholda May 14 '16 at 19:27
I would call it "taking successive quotients," but that's probably too vague to get any interesting hits. – Matt Samuel May 14 '16 at 19:30

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