This is exactly how we evaluate definite integrals. And when you look at it from this, you just see that it's, when you evaluate it, it just gives us the difference in temperature from zero minutes to 10 minutes. We're taking the temperature at 10 minutes, and from that we're subtracting from that the temperature at zero minutes. So this is really our change in temperature over the first, over those 10 minutes. And we can actually evaluate it. We know what our temperature was after 10 minutes. H of 10 is 43 degrees Celsius.