n choose n is going to be x to the 0 times delta x to the n. So that's the binomial expansion. And let me switch back to minus. So all of that, that green, that's x plus delta x to the n, so minus x to the n. Minus x to the n power, that's x to the n, I know I squashed it there. All of that over delta x. Let's see if we can simplify. So first of all, we have an x to the n here, and at the very end, we subtract out an x to the n, so these two cancel out. And then if we look at every term here, every term in the numerator has a delta x, right?