So going back to part A, use the data in the table to approximate the rate at which the temperature of the T is changing at time T equals 3.5. So the rate of change is really just the slope of this curve at time T is equal to 3.5. So really, we just want to find the slope at that point right over there. We want to find the slope. And we don't know the actual function, so the best way to approximate the slope at that point is really just find the slope between minute 5 and minute 2. So the rate of change, we could say that the rate is going to be approximately our change in temperature over those 3 minutes. So h of 5 minus h of 2, and this is obviously going to be in degrees Celsius, over the number of minutes that changed.