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. So we end at 5 minutes and we started at 2 minutes. And so the rate is going to be approximately at 5 minutes, our temperature is 52 degrees. At 2 minutes, our temperature is 60 degrees.