Translate each of the following into the language of derivatives, sketch a plot of the appropriate function and indicate the concavity.
(a) Water is evaporating from the tank at a constant rate.
(b) Water is being poured into the tank at 3 gallons per minute but is also leaking out at z gallon per minute.
(c) Since water is being poured into the conical tank at a constant rate, the water level is rising at a slower and slower rate.
(d) Inflation held steady this year but is expected to rise more and more rapidly in the years ahead.
(e) At present the price of oil is dropping, but this trend is expected to slow and then reverse direction in 2 years
(f) David's temperature is still rising, but the penicillin seems to be taking effect.