4 ms·That doesn't mean negative. The curve could be flat, then steeply rises to match LNT at some point.by queuebert 3y agoThat doesn't mean negative. The curve could be flat, then steeply rises to match LNT at some point.pfdietz 3y agoIt means that somewhere the second derivative must be negative (proof: take the derivative, then apply the mean value theorem of calculus)queuebert 3y agoYou're correct of course. I read that as first derivative for some reason.