> For a ship in the water, drag increases as the cube of speed...As your speed increases, your drag increases exponentially...
He's being inconsistent.
I've actually heard this a lot lately -- people will say something is "increasing exponentially" (i.e. has a curve of the form f(x) = k*b^x) when they really mean a much looser condition like "accelerating" (positive second derivative, which might be an exponential curve, but also might be one of many other curves, e.g. any polynomial of degree >= 2 with nonnegative coefficients).
It's almost as bad as people who talk about the "least common denominator," but that's a rant for another post.
I'm tempted to say that it's good enough for something where the reader won't need to do actual math with the information. He's just trying to get across the point that the drag increases faster than linearly. "Increases polynomially" would be more correct, but would get the message across to fewer readers. "Exponentially" is inaccurate, but conveys the message more accurately than any other phrasing that readily comes to mind.
And I'm tempted to say that what distinguishes math from most other forms of expression is precision, and if you're not going to be precise, you should avoid blatantly mathematical language.
> For a ship in the water, drag increases as the cube of speed...As your speed increases, your drag increases exponentially...
He's being inconsistent.
I've actually heard this a lot lately -- people will say something is "increasing exponentially" (i.e. has a curve of the form f(x) = k*b^x) when they really mean a much looser condition like "accelerating" (positive second derivative, which might be an exponential curve, but also might be one of many other curves, e.g. any polynomial of degree >= 2 with nonnegative coefficients).
It's almost as bad as people who talk about the "least common denominator," but that's a rant for another post.