The mass of a growing cyst at clock time t is given by m = .09 * t³, where m is mass in grams and t is clock time in months.

• At what average rate is the mass changing between clock times t = 9.5 and t = 9.6 months? 
• At what average rate is the mass changing between clock times t = 9.5 and t = 9.51 months? 
• At what average rate is the mass changing between clock times t = 9.5 and t = 9.501 months? 
• What do you estimate is the rate at which mass is changing at clock time t = 9.5 months?

The rate at which the mass of the cyst changes is given by Rate = .007 * t², where Rate is rate of change in grams per month and t is clock time in months.  How much do you think mass will change between t = 9.5 and t = 19 months?