um, if that’s supposed to be a derivative of f(g), then that should be the rate at which ice cream is made. specifically, at 200 gallons of ice cream, you are producing at a rate of 200 gals/ $1.4, or 143gal/dollar.
The last calc i had was calc III and that was a couple years ago and it was all crap so I don’t really remember. What do you want? Explain the significance of the statements at the bottom? or the meaning of the prime function?
although can have many f(x) = C can be the value of multiple x’s, you cannot possibly have multiple values for f(x) (otherwise you’d have a pretty screwed up slope =))