The article says that resisivity in normal metals follows a quadratic curve, but the article also says that it follows an exponential curve. Does anyone know which it right?
Typically, the behavior of any given metal is a mix of mechanisms so the measured behavior is fit to a curve where you fit n. So for metals the exponent is typically a decimal between 2 and 5.
But the specific word they were looking for is "quintic". (And the corresponding word for 4th-degree, in case anyone is curious, is "quartic"; one sometimes sees "biquadratic", which unfortunately is also sometimes used to describe a particular subset of quartics.)
Oh right, silly me. Wow, my own vocabulary deserted me there, huh?
Yeah I think generally "sextic" is the highest you see before people stop doing that, and that one's somewhat uncommon I'd say. ("Quintic" is actually fairly common, contrary to what I said earlier, oops.) The fact that seventh-degree would be "septic" might be one reason stop with the words at that point!
I'm pretty sure that more than half the times I've seen "quintic" are in one single context: talking about the fact that while you can solve polynomial equations of degree 1-4 by doing arithmetic and taking n'th roots, this stops being possible once you get as far as quintic equations. (The "insolubility of the quintic".)
No. Exponential growth or decay is much faster than quadratic growth or decay. You may be mixing up exponential functions, of the form x maps to ab^x, with power functions, of the form x maps to ax^b. These are very different!
Annoyingly, people often use "exponential" colloquially to mean anything faster than linear, but in fact lots of things are faster than linear.
From the other responses, it sounds like "none of the above". It's more like a "polynomial curve" that is only sometimes quadratic. Is "polynomial curve" a thing? "Power curve" / "power function"?
