So one way to think about it is we took the constant out of the integral, which we'll see in the future. Both of these are very useful techniques. Now, if you're satisfied with them as they are written, then that's fine, you can move on. If you want a little bit of a proof, what I'm going to do here to give an argument for why this is true is use the derivative properties. Take the derivative of both sides and see that the equality holds once we get rid of the integrals. So let's do that. Let's take the derivative with respect to x of both sides of this, derivative with respect to x.