And since there's no n out here, we could just take the limit of this and then take that to the a power, so that's going to be equal to the limit as n approaches infinity of 1 plus 1 over n to the nth power, all of that, to the a. And this is our definition, or one of the ways to get to e, if you watch the videos on compound interests and all of that. This is how we got to e. And if you try it on your calculator, just try larger and larger n's here, and you'll get e. So this is equal to, this inner part is equal to e. So, and we raised it to the a power, so it's equal to e to the a. So hopefully you're pretty satisfied that this limit is equal to e to the a. And then one other toolkit I want on our belt, and I'll probably actually do the proof in the next video, the other toolkit is to recognize that x factorial, let me do this, x factorial over x minus k factorial is equal to x times x minus 1 times x minus 2, all the way down to times x minus k plus 1. And we've done this a lot of times, but this is the most abstract we've ever written it. I can give you a couple of examples.