[benj111]

"and rate of rate of increase negative"

Are you a politician? Because that's a very round about way of putting it. :P

If the rate of increase is negative, there is an actual absolute decline. Is that want you were meaning to say?

[barrkel]

I said rate of rate of increase. The second derivative is negative at a local maximum.

https://en.wikipedia.org/wiki/Derivative_test#Second_derivat...

[caf]

...and the sign of the second derivative flips at an inflection point.

[benj111]

My mistake, I misread.

[antisemiotic]

"rate of rate of increase" = "second derivative", I presume. Negative second derivative doesn't necessarily mean a decline, it can be just growth slowing down.